Posters

We report on the X-ray analysis of PSR J1741-2054 carried out as a part of the Chandra XVP program (6 ACIS-S observations, totalling ~300 ks over 5 months). By registering this new epoch of observations using X-ray point sources in the field of view to an archival observation taken 3.2 years earlier, we are able to measure the proper motion of the pulsar with > 3 sigma significance. We also investigate the spatial and spectral properties of the pulsar, its compact nebula and extended tail. We find that the compact nebula can be well described with an absorbed power-law with photon index of Gamma=1.6+/-0.2, while the tail shows no evidence of variation in the spectral index with the distance from the pulsar. We have also investigated the X-ray spectrum of the neutron star.

Cross-correlating the radio timing positions of all known radio pulsars with archival X-ray observations, we identified new X-ray counterparts of radio pulsars. In most cases the archival data are too sparse to support a detailed spectral and timing analysis. About one-third of the new detections are millisecond-pulsars. The others belong to the group of Vela-like and middle-aged pulsars. Furthermore, we deduced upper limits of the X-ray flux for more than 200 other radio pulsars. This large sample enables us to study the X-ray efficiency of those sources and to put further constrains on models which describe the thermal evolution of neutron stars.

We present here preliminary results of the analysis of INTEGRAL observations of GRO J1744-28, the bursting pulsar, during the 2014 outburst.

Poster

Neutron stars are predicted to be stable over the mass range ≈0.1 to ≈3 M⊙. At 1.4 M⊙, 98% of the mass is in a core with supernuclear density and 1-2 % forms a thin crust and atmosphere. As mass decreases, the fraction of mass in the crust increases until at 0.1 M⊙, all material is at nuclear density or below and the star is all crust. Observationally, the masses of ≈ 60 neutron stars have been measured and all fall between 1 M⊙ and 2 M⊙. It is of interest to search for low-mass neutron stars, those with M < 0.5 M⊙. These should have different characteristics and might be found in high-mass binaries, as high-velocity objects, and perhaps as Magnetars.

Poster

We analyzed the Chandra ACIS data for the supernova remnant G266.2-1.2. The data for a portion of the northwestern rim indicate that it is expanding at the rate of 0.42 +/- 0.10 arcsec/yr (half the rate reported by Katsuda, Tsunemi & Mori (2008) for an analysis of XMM data). A hydrodynamic analysis was performed using broad ranges of initial kinetic energies, ejecta masses, ejecta mass density distributions, ambient densities, and evolutionary states. The results were constrained by the Chandra expansion rate (assuming it is representative of the remnant as a whole), an inferred lower limit on the forward shock speed, an upper limit on the inferred thermal X-ray emission, and energy considerations. The results suggest that G266.2-1.2 is most likely between 2.4 and 5.1 kyr old.

Poster

Chandra has revealed highly asymmetric supernova ejecta in G1.9+0.3. Iron dominates thermal emission in the radio-bright northern rim, while only intermediate-mass elements are found along the SE-NW axis. The measured X-ray expansion rates decrease radially by about 60% along this axis from 0.84% yr^(-1) to 0.52% yr^(-1). This corresponds to undecelerated ages of 120 - 190 yr, confirming the young age of G1.9+0.3, and implying that the blast wave is much more decelerated than the reverse shock. Only the outermost ejecta with very high (>18,000 km s^(-1)) free-expansion velocities have been shocked so far. We discuss G1.9+0.3 in the framework of recent asymmetric 3D delayed-detonation Type Ia explosions from Seitenzahl et al. (2013). Their N3 model provides the best match.

Poster

We present a spectral analysis of the X-ray brightest Supernova Remnants (SNRs) in the nearby, spiral galaxy M33 from our deep XMM-Newton survey that complements our previous survey with Chandra (ChASeM33) by covering the entire galaxy. We have simultaneously fit the XMM and Chandra spectra (when available) to better constrain the fitted parameters. We do not find any young (t<1,000 yr) SNRs that could be analogs of Cas A or the Crab, but we find several older SNRs that show evidence of enhanced abundances. These bright X-ray SNRs appear to occur in regions with a higher than average ISM density, assuming they are in the Sedov phase. We include the first detailed spectral analysis of the third most luminous X-ray SNR in M33, which was outside the ChASeM33 survey area.

G327.1-1.1 is a composite SNR containing a symmetric radio shell and a PWN that has likely been disrupted by the reverse shock. Previous X-ray studies reveled a complex morphology; a compact core embedded in bow-shock-like structure, prong-like features extending into large arcs, and thermal emission from the SNR shell. We present deep, 350 ks Chandra observations of G327.1-1.1 that provide new information about the properties of the system, such as the spatial variations in the spectral index across the observed PWN structures, and the thermal temperature across the SNR shell. We also present preliminary HD simulations of an asymmetric PWN/SNR interaction in a system with a moving pulsar, expanding into a non-uniform ISM density, which offer new insight into the nature of the remnant.

Subsequent to the detections AGILE and Fermi/LAT of the gamma-ray flares from the Crab Nebula in the fall of 2010, this team has been monitoring the X-Ray emission from the Crab on a regular basis. Initially X-Ray observations took place once per month when viewing constraints allowed. More recently observations with Chandra and HST have taken place four times per year. There have been notable exceptions, e.g. in April of 2011 and March 2013 when we initiated a set of Chandra Target of opportunity observations in conjunction with bright gamma-ray flares. Often Keck observations were obtained. The aim of this program to characterize, in depth, the X-ray, optical, and infrared variations that take place in the nebula, and, by so doing, determine the regions which contribute to the harder X-ray variations and, if possible, determine the precise location within the Nebula of the origin of the gamma-ray flares. As part of this project members of the team have applied Singular Value Decomposition techniques to sequences of images in order to more accurately characterize features and their behavior. The current status of the project will be discussed highlighting studies of the inner knot and possible correlations with the gamma-ray flares.

Nearby Alpha Centauri is destined for a pivotal chapter in human history, as first stop of future starfarers from Earth: 3x closer than the next nearest star; three very different objects to visit -- Alpha Cen A (G2V), B (K1V), and C (M6V); and B hosts an Earth-mass companion, albeit in a hot, lifeless orbit. For its part, Chandra has been keeping intent watch on the high-energy starspot cycles of AB, with semi-annual pointings over the past decade. Only HRC-I can separate AB as they plunge toward a close approach of 4'' in 2016; and LETGS has countered that an abrupt 50x drop in XMM count rate of sun-like A in early 2005, ominously reported as the "darkening of the solar twin," simply is a soft sensitivity issue, not an unprecedented, inexplicable case of corona interrupta.

Poster

30 Doradus is the most important star-forming complex in the Local Group, offering a microscope on starburst astrophysics. At its heart is R136, the most massive resolved stellar cluster, containing the most massive stars known. Across 30~Dor's 250-pc extent, stellar winds and supernovae have carved its ISM into an amazing display of arcs, pillars, and bubbles. Chandra is observing 30~Dor this year for the 2-Ms AO15 XVP "T-ReX". This deep observation will finally exploit Chandra's fine spatial resolution to study ISM interfaces on 1--10 pc scales, the full complement of massive stars, and the brightest pre-main sequence stars that trace 25~Myrs of star formation in this incomparable nearby starburst. Here we give preliminary results from the first 900~ks of Chandra observations.

Poster

X-ray flux provides a decisive diagnostic to separate old low-mass field stars from young low mass stars which were formed at the same time as massive stars (Cepheids). We have used this to investigate two aspects of these 6 Msun stars which have implications for star formation: resolved companions and larger stellar groups (clusters and association remnants). We have observed 11 Cepheids with Chandra and XMM which have possible resolved companions. X-ray active low mass stars were ONLY found within 6300 AU of the Cepheid, establishing an outer limit for gravitationally bound companions. For clusters, we have identified low mass members of a new cluster containing S Mus, as well as possible cluster remnants around several other Cepheids.

Evolution of pre-cataclysmic and cataclysmic binaries is thought to be dominated by orbital angular momentum loss through coronally-driven winds of the late-type secondary star. However, coronal activity of stars at the extremes of rotation found in cataclysmic variables (CVs) remains essentially unexplored: existing studies reach to rotation periods of 0.3-0.2 days - significantly longer than the periods of CVs. The aim of this study is to explore the X-ray supersaturation regime close to 0.1 day periods using short Chandra snapshot observations for a small sample of the fastest rotating stars outside of accreting systems. We will present the results and discuss their relevance for understanding the timescales of CV evolution and the possible road to Type 1a supernovae.

The Chandra Planetary Nebula Survey (ChanPlaNS) has established that diffuse X-ray emission, generated by energetic, nebula-shaping wind shocks, emanates from ~1/4 of planetary nebulae (PNe). Such X-ray emission sources are found only in the youngest, most compact nebulae with the highest nebular densities, implying active PN "sculpting" lifetimes of \<~5000 years. The diffuse X-ray detection rate is 100% for the (five) ChanPlaNS sample PNe with Wolf-Rayet ([WR]) type central stars. We present preliminary results from 3D structural reconstructions of PNe that are designed to investigate the apparent systematic differences between the diffuse X-ray emission morphologies of PNe with [WR] vs. non-[WR] central stars, as well as the possibility of enhanced, intranebular X-ray absorption.

The Chandra Galactic Bulge Survey (GBS) is a shallow survey with a flux limit of 1e-14 erg/cm2/s (0.5-10.0 keV) that covers a pair of 6 sq. deg. areas centred 1.5 deg. above and below the Galactic Center. The extinction and crowding in these regions are such that optical/infrared counterparts to the 1640 X-ray sources found with Chandra are accessible to detailed follow-up. The GBS is designed to set constraints on four important areas in astrophysics: stellar-mass black hole formation, the neutron star equation of state, the nature of the progenitors of type Ia supernovae and the common envelope evolution. Here I present the survey properties and goals, our multiwavelength methods to identify and clasify the counterparts to the X-ray sources and the first scientific results.

A quantitative description of the stellar age-rotation-magnetic activity relation (ARAR) is a work in progress. Empirical calibrations of it rely on observations of co-eval populations of stars in open clusters. ROSAT observations were used to characterize coronal X-ray emission, a tracer of a star's magnetic activity, in the ~500-Myr-old Hyades and Praesepe clusters. These data differ a lot, casting doubt on the universality of the age-activity relation. We present our results from a Chandra observation of the 500-Myr-old M37 cluster. We observed it for 450 ksec using the ACIS-I chips and detected 250 cluster members. We use our data and public M37 rotation periods catalogs to decouple the age-rotation and rotation-activity relations, and to determine the universality of the 500-Myr ARAR.

Poster

QV Nor is the B0I donor of the HMXB 4U1538-52. The neutron star orbits its massive companion in less than 4 days probing, along its eccentric orbit, the innermost (r < 1.4R*) wind regions of the stellar wind. In this work we will present the first high resolution X-ray spectrum of QV Nor, using Chandra HETG. We will present and analysis of the emission lines arising in its photoionized wind as well as the fluorescence Fe K alpha line probing the dense and cold matter. The implications for the wind structure in early type stars will be discussed.

We are carrying out an X-ray survey of old open clusters (OCs) with the Chandra X-ray Observatory. Single old stars emit very faint X-rays, making X-rays produced by mass transfer in CVs, or by rapid rotation of the stars in tidally-locked, detached binaries detectable, without contamination from single stars. By comparing properties of interacting binaries in different environments, we aim to study binary evolution, and how dynamical encounters with other cluster members affect it. Collinder (Cr) 261 is an old OC(~7Gyr), with one of the richest populations inferred, of close binary populations and blue stragglers of all OCs. We will present the first results, detailing the X-ray population of Cr 261, in conjugation with other OCs, and in comparison with populations in globular clusters.

Diffuse X-ray Emission in Massive Star-Forming Regions Chandra is providing remarkable new views of massive star-forming regions, revealing the effects of massive star feedback on natal molecular filaments and clouds. We will explore the extensive Chandra data on such regions, highlighting processes that characterize the life of a massive stellar cluster, from ultracompact HII regions to superbubbles so large that they shape our views of galaxies. These complexes are suffused by parsec-scale diffuse X-ray emission outlined (and sometimes confined) by colder structures seen in long-wavelength images; these are the long-sought signatures of multi-million-degree plasmas created by fast O-star winds. They show us the birth of the hot interstellar medium.

Poster

We present results from a Chandra Visionary Project to study the X-ray source populations in the Small Magellanic Cloud (SMC) down to unprecedented luminosity limit of 5x10^(32) erg/s in fields with young (<100 Myr) stellar populations of different ages. We detect 50-100 sources per field and measure their X-ray photometric and spectroscopic parameters. Light curve analysis is used to identify accreting pulsars and flaring objects. Based on source multi-wavelength properties, we identify high-mass X-ray binaries (XRBs) and study their connection with star-forming regions. These data provide the deepest X-ray luminosity functions for XRBs in a low metallicity (0.2Z\sun) star-forming galaxy and allow us to measure the formation efficiency of young XRBs and its evolution with time.

Poster

The Nuclear Spectroscopic Telescope Array (NuSTAR) has performed extensive observations of our Galactic Center. NuSTAR's unique ability to produce high-energy X-ray spectra with fast timing resolution and sub-arcminute angular resolution, combined with higher angular resolution observations made with Chandra and XMM-Newton in low-energy X-rays plus VLA observations in the radio waveband, have yielded important insights into a variety of energetic phenomena in this region. Here we describe what has been learned about Sgr A* flares, the candidate pulsar wind nebula CXOGC J174545.5-285829, aka "the Cannonball", and the nonthermal filament Sgr A-E (G359.89-0.08).

We present the discovery of luminous (7e39 - 5e40 ergs/s), very brief (1-10 minute) X-ray flares in two extragalactic globular clusters discovered with Chandra. While brief in duration, these outbursts represent the most energetic events ever recorded in globular clusters, temporarily increasing the luminosity of the source by a factor of 100-200. Such powerful rapid variability is rivaled only by gamma-ray bursts and outbursts from soft gamma repeaters, yet these sources show little resemblance to these two classes of objects. Instead, the outbursts resemble Type 1 bursts seen in Galactic neutron stars, but scaled up in luminosity by two orders of magnitude. We discuss the origin of these sources, and their possible connection to black holes within globular clusters.

The galaxy M51 is perhaps the best example of a major interacting galaxy in the nearby universe. We present our efforts to date to characterize the discrete X-ray source population of M51 using new data from a Chandra Very Large Project (PI Kuntz). When combined with archival data, we reach a total exposure of 865 ksec, representing the deepest exposure in high-resolution X-ray of the full disk of any spiral galaxy. Here we highlight our catalog and processing efforts and present initial results.

The hot ISM in early type galaxies (ETGs) plays a crucial role in understanding their formation and evolution. Structural features of the hot ISM identified by Chandra (including jets, cavities, cold fronts, filaments and tails) point to key evolutionary mechanisms, e.g., AGN feedback, merging history, accretion/stripping and star formation and its quenching. In our new project, the Chandra Galaxy Atlas, we will systematically analyze the archival Chandra data of 137 ETGs to study the hot ISM. Taking full advantage of the Chandra capabilities, we will derive uniform data products of spatially resolved datasets with additional spectral information. We will make these products publicly available and use them for our focused science goals.

Poster

Diffuse X-ray emission in the disks of late-type spiral galaxies is not well understood. Correlations exist between the X-ray surface brightness (X) the FUV surface brightness (U), the X-ray hardness (H) and the galactocentric radius (R). We have used deep Chandra observations of three nearby face-on galaxies, M101, M83, and M51 to understand the relations among the observed correlations. In particular, we find that at a given galactocentric radius X=A U^0.5, and the normalization, A, decreases with radius, more strongly in galaxies with short disk scale-lengths than in those with long scale-lengths. H seems to show more variation with R than with the local density, probably due to the long cooling time. Both of these correlations appear to be mediated by the mid-plane density.

We study the unresolved X-ray emission from three Local Group dwarf elliptical galaxies (NGC147, NGC185 and NGC205), which is thought to originate from a collection of weak X-ray sources primarily consisting of cataclysmic variables and coronally active binaries. The derived 0.5-2 keV X-ray emissivities (per unit stellar mass) of these dwarfs are comparable to that in the Solar neighborhood, but are significantly higher than the average cumulative emissivity of X-ray sources in four Galactic globular clusters, indicating a reduced binary fraction in the latter. Our results are also important for studies of the apparently diffuse X-ray emission in nearby normal galaxies.

Poster

The cores of globular clusters (GCs) are perfect places to study dynamical interactions between stars because of the high stellar densities (up to 10E6 stars/pc3). In this work we use new near-ultraviolet images of the massive GC 47 Tuc obtained with the Hubble Space Telescope (HST), Chandra X-ray data and optical HST data to study the compact binaries in 47 Tuc, especially the population of faint cataclysmic variableS (CVs). These data allow us to obtain one of the deepest measurements of the globular-cluster CV luminosity function, which we compare with the measured CV luminosity function in the field and with those of other GCs. Our aim is to explore the effects of dynamical interactions on the formation and evolution of compact binary populations, in particular on that of CVs.

Poster

We present our study of low-mass X-ray binaries (LMXBs) in NGC 3115 using the Ms Chandra XVP observations. By systematically comparing their spectral dependence on luminosity with those of Galactic X-ray binaries, we show that most bright sources in NGC 3115 are neutron star LMXBs in the soft state, except ten that are probably black hole LMXBs due to very soft spectra. We construct the X-ray luminosity function (XLF) down to the limit of ~10^36 erg/s, and show significant flattening of the overall XLF from dN/dL \propto L^2.2 above 6X10^37 erg/s to dN/dL \propto L^1.0 below it. The XLF of globular cluster LMXBs is flatter than the field XLF, indicating their different origins. We also observed spatial variation of field XLFs. We discuss the physical implications of all these results.

Poster

We have reanalyzed 83 observations of M87 taken by Chandra from 2000 July to 2014 March. Preliminary results from light curves for each knot in 3 energy bands include: (a) The spectrum of HST-1 is harder during the rise of the giant flare of 2005 than during the decay. (b) There is a 2 year segment during which the decay rates in the 3 energy bands are consistent with synchrotron losses from a magnetic field of 1 to 10 mG. (c) Knot D is increasing slowly. (d) Knot A is slowly fading. (e) Knot M, the "Maverick" is not part of the jet; rather it is an obstacle that deflects the jet (both radio and optical). It has a harder spectrum than other knots and it has no detectable optical or radio emission. This work was supported by NASA grants GO2-13133X, GO3-14106X, and GO4-15095X.

I will present studies of connections between star formation (SF) and supermassive black hole (SMBH) accretion in galaxies, using large galaxy and AGN samples from the wide-field Boötes survey. We find a linear relationship between galactic SF rate and the average SMBH accretion rate, consistent with a strong physical connection between these processes despite the fact that SMBH and galaxy growth rates in individual AGN host galaxies are not directly correlated due to the short variability timescale of AGN relative to SF. I will also present evidence for a link between nuclear obscuration and host galaxy SF in powerful quasars. These results support a scenario in which galaxy and SMBH grow from a common gas reservoir that can obscure the central SMBH during the luminous quasar phase.

Poster

The unique imaging capabilities of Chandra have been successfully used to perform microlensing studies of distant QSOs. The main aim was to infer the dimensions of their X-ray emitting regions. Using data from the Chandra archive, we built-up an XMM-Newton program devoted to using the magnification due to gravitational lenses to characterize in detail the broad band spectra and variability of distant AGN. Here we present preliminary results of the XMM-Newton observation of QSO B1422+231 at z=3.62.

Many models require a close link between the growth of BHs and their host galaxies through feedback processes. These active galactic nuclei (AGN) are capable of releasing enormous quantities of energy over their lifetimes, often comparable to the binding energy of their hosts. We have performed a set of statistical population analyses that combines Chandra's exquisite angular resolution with available multi-wavelength data across over 100 deg^2 of the sky, to build the most complete view of AGN and their host galaxies throughout the last 9 Gyrs. We show that galaxy evolution proceeds similarly with or without the inclusion of an AGN, but through X-ray stacking, we also find that many AGN still remain hidden even in the most nearby galaxies, lying below typical AGN detection thresholds.

Centaurus A is the closest radio-loud active galactic nucleus (AGN). At a distance of 3.8 Mpc the angular resolution of 0.5 arcsec of Chandra/ACIS translates into ~10 pc. This gives us the unique opportunity to disentangle the X-ray emission from different components. We analyzed archival data (2000-2013) and study timing and spectral properties of the core region and the diffuse gas in Cen A. Using the soft X-ray emission lines, we study the nature of this diffuse material. The core region of Cen A emits time- and spectrally-variable hard X-rays. We report that a circumnuclear "halo" (up to 0.5 kpc away from the core) also emits an Fe K-alpha line, and we investigate the nature of this emission.

Poster

Similarities between the observational accretion signatures of X-ray Binary (XRB) systems and active galactic nuclei (AGN) are still ardently sought. XRB spectral states show an inflected correlation between X-ray spectral hardness and Eddington ratio. Large AGN samples may also serve to catch supermassive black hole accretion in different states. We discuss and lambaste recent such tests, including our own using the Chandra Source Catalog and SDSS, of such analogies. Significant strides can and must be made, and we delineate related plans and hopes using SDSS spectroscopy and wide-area X-ray imaging.

Poster

We are undertaking a large area X-ray survey overlapping SDSS Stripe 82, a region rich with multi-wavelength coverage and high optical spectroscopic completeness. The current X-ray coverage in Stripe 82 is 16.5 deg^2, from archival Chandra and archival and proprietary XMM-Newton data. In the coming year, another 20 deg^2 will be added to our survey with XMM-Newton, as well as ~2 deg^2 from Chandra GTO observations. "Stripe 82X" finds more rare, high luminosity AGN than some models predict should exist. I will highlight the contribution of Chandra data in discovering high luminosity AGN and optically dull, infrared bright sources, revealing the often over-looked, though important, population of growing supermassive black holes.

Poster

We present a 70 ks Chandra observation of the radio galaxy 3C293. This galaxy contains 3.7 x 10^9 solar masses of 100 K molecular hydrogen in an extended 10 kpc scale region, heated by jet-driven shocks. With Chandra, we observe emission from the jets both within and outside the host galaxy to study the effect of jet feedback on the ISM. We model the spectra of the nucleus, the inner jets, and the X-ray features along the 100-kpc radio jets. The nucleus and inner jets show evidence of 10^7 K shock-heated gas. The jets' kinetic power is more than sufficient to heat the X-ray emitting gas, which serves as a reservoir of thermal and turbulent energy to maintain the molecular hydrogen emission over 10^7 years. We examine the connection between the X-ray and molecular hydrogen emissions.

Poster

The source 2XMMi J184725.1-631724 was serendipitously detected in two XMM-Newton observations in 2006-2007. It is a tidal disruption event (TDE) candidate because of its ultrasoft X-ray spectra (kT ~ 0.07-0.09 keV), high peak luminosity (~10^44 erg/s), possible transient nature, coincidence with an inactive galaxy, Here we report the multiwavelength follow-up observations of the event. Especially, our 2013 Chandra observation indicates that the 0.2-10 keV flux of our source has decreased by a factor of more than 500 from the peak, confirming its transient nature. Our XMM-Newton and Swift observations also detectd a UV source, which seems blue and is fainter in 2013 than near the peak, thus most likely associated with the event. Such UV emission was seldom detected in X-ray detected TDEs.

Poster

The physical origin of the X-ray emission in powerful quasar jets has been a long-standing mystery. Though these jets start out on the sub-pc scale as highly relativistic flows, we do not have any direct measurement of their speeds on the kpc scale, where the vast distances from the core necessitate in situ particle acceleration. If the jets remain highly relativistic, then the X-rays could be due to inverse-Compton off the CMB. However, the IC/CMB explanation also predicts a high level of gamma-ray emission, which has been ruled out in several cases, including the famous source 3C 273 (Meyer & Georganopoulos 2014), suggesting the X-rays are synchrotron in origin. I will discuss the surprising implications of these findings for the energetics and radiative output of powerful quasars.

Poster

We present a spectral analysis of the 118 ks High Energy Transmission Gratings (HETG) observation of the X-ray bright Seyfert 1.5 galaxy MCG +8-11-11, in conjunction with 100 ks of archival Suzaku data. Fe K-alpha line emission is clearly detected and is likely resolved by the HETG. The data are consistent with reprocessing by a distant, neutral torus that is marginally Compton thick and out of the line-of-sight. We do not find compelling evidence of a relativistically-broadened Fe-K emission line and, contrary to previous results, warm absorption is not required by the data. The HETG data are consistent with the presence of a soft excess, a feature that may be missed by considering Suzaku data alone.

We present a stacking analysis of Chandra data for the complete sample of Early Type Galaxies (ETGs) in C-COSMOS to explore the relation between the X-ray luminosity of the hot gas halos and the stellar luminosity in these sources for 0<z<1.5. In the local universe this relation suggests the presence of virialized halos for nearby ETGs, while a recent analysis of X-ray detected ETGs in C-COSMOS showed that more luminous ETGs tend to diverge from the local relation, with enhanced X-ray emission likely due to hidden AGN or evolution of hot halos. The results of our analysis reveal enhanced X-ray luminosities also for a population of less luminous ETGs, with increased HR suggesting contribution to X-ray emission by AGN with M_BH~10^{7\div 8}M_{\astrosun} and \dot{m}\sim{10}^{-4}.

Poster

The 4 Msec (soon 7 Msec) Chandra Deep Field South is the deepest X-ray image of the sky and one of the extraordinary legacies of the first 15 years of Chandra. The CDFS tracks the growth of supermassive black holes and can potentially shed light on the formation of seed black holes and their first growth episodes. Recent efforts to locate these first growth spurts in the deepest Chandra surveys are yielding increasingly strong constraints on seed formation models that start to challenge theory. Most surprising is the lack of any evidence for black hole accretion in z>5 galaxies. At the same time, observations of intermediate redshift galaxies with Chandra may hold clues to how and when normal mass black holes - like that at the center of the Milky Way - formed and grew up.

We present the results from morphological studies of X-ray jets observed in the two highest redshift quasars with Chandra X-ray Observatory. We apply a novel computational technique to work with low counts Poisson images and separate jet emission from a strong quasar core. The X-ray angular resolution matches the resolution of the radio maps allowing for direct studies of the location of X-ray and radio jet emission. We attempt to constrain the parameters of the jet emission process and estimate a jet power for these jets.

Poster

We present results of a deep Chandra observation of a low-z radio galaxy with signs of the complex interactions between the radio plasma and ISM. The Chandra image shows regions of enhanced X-ray emission correlated with radio structures along the jet axis. The larger scale X-ray diffuse emission outside the radio source correlates with the morphology of known optical line-emitting regions. We measure the temperature of the ISM and identify regions heated by weak shocks with the Mach number of 1.6. The X-ray emitting gas is most likely heated by the radio source expanding within this galaxy. The multi-band data supply a complex view of the source, signaling feedback processes closely associated with the central active nucleus.

Poster

We investigate the Eddington ratio distribution of X-ray selected broad-line AGNs in the redshift range 1.0<z<2.2, where the number density of AGNs peaks. Combining the optical and Subaru/FMOS near-infrared spectroscopy, we estimate black hole masses for broad-line AGNs in the CDFS, ECDFS, and the XMM-LH surveys. AGNs with similar black hole masses show a broad range of AGN bolometric luminosities, indicating that the accretion efficiency of black holes is widely distributed. We propose that the observed downsizing trend can be interpreted as massive black holes with low accretion rates, which are relatively fainter than less massive black holes with efficient accretion.

Poster

The circum-nuclear region in active galaxies is often complex with presence of high excitation gas, collimated radio outflow, and star forming regions, besides the active central supermassive black hole. In Chandra studies of a number of archetypal Seyfert galaxies to investigate AGN-host galaxy interaction, we were able to evaluate the mass outflow rate and shock heating by radio jet. For galaxies in the throes of a violent merging event such as NGC6240, we were able to resolve 70MK hot gas surrounding the double nuclei and discovered a large scale soft X-ray halo. The unique resolving power of Chandra also enables more discovery of such dual AGN systems and signs of past AGN outburst activities.

The study of galaxy cluster merger events is of major astrophysical interest as they have a profound and long-lasting impact on the thermodynamic evolution of the ICM. Observed as part of our large Chandra XVP program on the Planck ESZ sample, we discovered that the cluster A3411 is undergoing a spectacular merger event. Radio observations also reveal the presence of large-scale diffuse emission, suggesting the presence of shocks and turbulence in the ICM. Most interestingly, in the Chandra observations we indeed find evidence of a brightness discontinuity, roughly at the location of the radio emission. This suggests that a shock could be responsible for the acceleration of particles to relativistic energies and makes A3411 an ideal laboratory to study this poorly understood process.

Poster

A1758 comprises two X-ray luminous clusters (A1758N and A1758S) which are probably gravitationally bound. A deep Chandra observation shows that both A1758N and A1758S are undergoing major mergers. The merger in A1758N is at an advanced stage with heavily stripped cores and shock heated gas at large radii. In contrast, the merger in A1758S is at an early stage with shocked gas confined to the region between the merging cores. X-ray emission is also detected between A1758N and A1758S. The combined mass of A1758N and A1758S is comparable to the Coma cluster, which is one of the most massive clusters in the near by universe. Thus, our deep Chandra observation of A1758 is a window into the formation of the most massive systems presently residing in the local universe.

Recent studies have traced the hot ICM to the virial radius in a number of galaxy clusters. These results have begun to clarify the thermodynamic conditions at the edge of clusters, constraining models of cluster growth and evolution. We are embarked on a program to observe a sample of relaxed clusters with Suzaku, fully imaging each cluster to beyond R200, and leveraging complementary data from XMM-Newton and Chandra. We see indications of low-entropy substructures and azimuthal variations in temperature and surface brightness. I will present the latest results from this project, explore the possible sources of systematic error, and discuss the remarkable "universality" of thermodynamic profiles to the outer limits of galaxy clusters.

Poster

Based on the Chandra data for Cygnus A, I will discuss findings concerning its jets, inflation of its radio lobes and their interactions with its cluster atmosphere. While the inner parts of its cocoon shocks emit mainly thermal X-rays, in the more remote parts the emission is primarily nonthermal. Its inner X-ray cavities support models that produce strong backflows from the radio/X-ray hotspots. X-ray jets revealed by Chandra are best explained by synchrotron emission models that require large powers to be flowing through the jets. This implies that the primary energy flow in Cygnus A is via the X-ray jets rather than its radio jets. Estimates will be presented for key jet parameters based on matching the X-ray jets to the hotspots.

X-ray data from Abell 98 show a galaxy cluster with a bright north subcluster (A98N), a disturbed south subcluster (A98S), and a faint far south subcluster (A98SS). Surface brightness and temperature asymmetries in A98N show a region consistent with shock-heating created by an early stage merger of A98N and A98S. A98S has an asymmetric temperature structure due to a separate ongoing merger, also seen in optical data. It also has a wide-angle tail radio source from an AGN. A lobe is evacuating a cavity, suggesting AGN feedback. The subclusters project along a line, suggesting a large-scale filament. A surface brightness profile of emission between A98N and A98S is consistent with overlap between extended gas haloes. A98N and A98S are bound with 67% probability; A98S and A98SS are not bound.

The public ACCEPT database of cluster properties (Cavagnolo et al. 2008, 2009) included radial profiles of temperature, density,entropy, and cooling time. With the new ACCEPT2 project we are currently doubling the number of clusters in ACCEPT and expanding the current suite of properties to include uniformly measured profiles of mass along with signatures of dynamical relaxation (centroid shift, power ratios, surface brightness ! concentration, temperature ratios) and global quantities such as core-excised temperatures, X- ray luminosities, and metallicities. This project has the potential of yielding key results on the physics of galaxy clusters and cosmology and represent a benchmark for years to come, here we are highlighting the first early results ! obtained on the evolution of metal abundance content, the evolution of X-ray scaling relations, and the relation between cool cores and dynamical relaxation.

Poster

We present results from a 2 day observation of SS 433 in the X-ray using Chandra. SS 433 is an X-ray binary with strong, Doppler shifted emission lines from a highly collimated jet. Past observations at radio frequencies have shown that the jets form from discrete clumps, whereas X-ray observations have shown that the Doppler shift of jets changes smoothly through time. In order to address this relationship, this observation was made concurrently with radio observations made with the VLBA. The simultaneous data sets allow for evaluating several scenarios that aim to explain how the continuously evolving jet direction and speed is related to the formation of discrete features.

RT Cru is a member of a new sub-class of symbiotic interacting binaries with copious hard X-ray emission. It consists of a high-mass WD (>1.3 Ms) accreting from the wind of an M giant, and it is an important system to study in order to constrain precursor conditions for asymmetric PN and SN Ia. The Chandra HRC-I observation (Dec 2012), and an overlapping Swift observation, detected intermittent soft X-ray flaring, and we find evidence for a significant soft component in the spectrum. The flaring could be a consequence of clumped absorption columns moving in and out of the line of sight, or the variations could be due to changes at the accretion boundary layer. Further observations are needed to determine the origin of the soft emission and its relation to the hard emission.

Poster

Chandra thanks to its angular resolution, sensitivity and endurance has been able to monitor individual X-ray binaries in the starburst galaxy IC 10. The WR+BH binary known as IC10 X-1 is regarded as one of the most massive stellar black holes; a class of objects representing the pinnacle of the stellar mass function. BH binaries occupy key roles in seeding SMBHs, producing long GRBs at birth, and gravitational waves at death. We report our use of Chandra to refine the orbital ephemeris of X1 and match-up the radial velocity curve of the optical spectral lines with the X-ray eclipse. The resulting phase offset has fascinating implications for our understanding of the interactions between the WR star, its wind, and the radiation field of the BH.

Poster

We use the best available X-ray data from an intermediate polar to study the cooling-flow model often applied to model their X-ray spectra. After deriving the EMD from different models, we calculate line fluxes and H-like to He-like line ratios and compare them with a 496 ks Chandra/HETG observation of the intermediate polar EX~Hya. We find that the H/He ratios are not well reproduced by simple isobaric cooling flow models. We discuss and discard mechanisms such as photoionization, resonant scattering, and Compton cooling. Thermal conduction transfers energy from the region above 10$^{7.0}$, where the H-like lines are mostly formed, to the cooler region where the He-like ions of the lower-Z elements are formed, so it at least partly resolves the problem.

Recently, Díaz Trigo et al. reported the discovery of relativistic baryons in a jet in XMM/ATCA observations of the 2012 outburst of the black hole 4U 1630-47. We present a search for a similarly massive jet earlier in the same outburst using high-resolution X-ray spectra from the Chandra HETGS. Despite a detection of radio emission with ATCA, we find no evidence of a heavy jet in the X-ray spectrum, with tight upper limits on the relativistic emission lines seen by Díaz Trigo eight months later. Instead, we find deep absorption lines from a massive, highly ionized disk wind, whose properties can be probed with detailed photoionization models. We explore several scenarios to explain the two modes of massive outflow in this remarkable black hole system.

Poster

The High Mass X-ray Binary, Black Hole Candidate (BHC) system LMC X-1 is among those that has been claimed to exhibit evidence for near maximal spin. However, compared to other systems, LMC X-1 is rather unusual in that it never shows evidence for ever reaching a "stable" minimum effective area. Here we discuss a series of Chandra-High Energy Transmission Gratings observations that cover a number of different orbital phases. We find spectroscopic evidence for emission from the high mass companion's wind. Additionally, we explore whether there is orbital phase-dependent absorption by this wind, as has been previously suggested. Finally, we use Comptonization models to describe the continuum spectrum, and discuss those aspects of the fits that are driving the suggestion for maximal spin.

Poster

Jets powered by high-mass X-ray binaries must traverse the powerful wind of the companion star. We present the first global 3D simulations of jet-wind interaction in high-mass X-ray binaries. We show that the jet can be re-collimated where the internal jet pressure is equal to the wind ram pressure, and beyond the re-collimation, the jet thickness follows from pressure equilibrium between the jet and bow-shock. From this analytic jet model, we analyze the effects of jet-wind interaction, bending the jet to an asymptotic angle f. Through both numerical and analytic approach, we formularize the angle f as a function of jet and wind parameters, which can be used to constrain the jet power. We apply the formula to the case of Cyg X-1 and Cyg X-3, and estimate the minimum jet power.

Cygnus X-3 is an X-ray binary (XRB) containing a stellar-mass compact object, likely a black hole, and a Wolf-Rayet star, which produces collimated, relativistic jets, placing it in the sub-class of XRBs known as microquasars. During a Chandra and Swift/XRT monitoring program, a soft X-ray excess (below 1 keV) was observed at certain states and phases of activity. This soft excess seems similar to the soft emission seen in Seyfert galaxies. The presence of these features would argue for a greater support of the black-hole nature of the compact object and serve to highlight the similarities of microquasars and AGN. We show the results of our studies of these soft excesses, as well as the changes of the X-ray Fe line region (6.4-7.0 keV) in function of the state activity and orbital phase.

Poster

Binary systems with a compact object are a unique chance to investigate the strong, clumpy, line-driven winds of early type supergiants by using the compact object's X-rays as a probe of the wind structure. Here, we analyze the two-component wind of HDE 226868, the O9.7Iab giant companion of the black hole Cyg X-1. Using Chandra-HETG we separate signatures of the hot gas phase from that due to additional absorption by the clumps and, using 5 hard state observations, study orbital variations and thus the spatial structure of the wind. Using ~4.8 Msec of RXTE data we probe the orbital variability of the wind on 2 ksec time scales throughout different accretion regimes of the black hole. We review our results in the light of current focused wind models and models for winds of O/B type stars.

Poster

The Chandra Science and Flight Operations Teams face a continual challenge in scheduling peer-reviewed and TOO observations while maintaining a safe thermal environment for all spacecraft components. Due to degradation of the silverized insulation that protects Chandra from the extremes of space, overall spacecraft temperatures have been increasing steadily since launch. The heating of different components depends on pitch angle, so staying within thermal limits is a delicate balancing act. A key part of the observation planning process is predicting on-board temperatures using the Xija thermal modeling framework which allows time-series modeling using pluggable components written in Python. In this poster we describe Xija and how it is used to make your Chandra observations happen.

Poster

X-rays are uniquely suited for studying interstellar metals, significant fraction of which are locked up in dust. I will focus primarily on the phenomenon of X-ray scattering by dust, which produces a diffuse arcminute scale halo around bright point sources that lie behind a sufficient dust column. The scattering cross-section is most sensitive to large grains, for which the size distribution cannot be constrained with UV, optical, and infrared studies. Chandra has a compact PSF and unsurpassed spatial resolution, making it uniquely suited for studying dust scattering halos. I will demonstrate how a Bayesian analysis of a scattering halo profile can be used to measure the upper limit to the grain size distribution and provide insights to the spatial distribution of diffuse ISM dust.

Poster

Chandra High Energy Transmission Grating (HETG) spectra of most sources reveal ISM lines and edges of dozens of atomic species at extraordinary precision. Our analyses of X-ray binaries have yielded the first detection of the K-alpha, K-beta, and K-gamma resonances in several ionic species. In particular, our studies of the O I absorption lines have brought to light an outstanding discrepancy between observation, theory and laboratory data: In a novel use of Chandra data, we have identified these lines, benchmarked their wavelengths and thereby improved model reliability. Additionally, using the superb Chandra data we have calibrated our cross sections for the Ne K-, Fe L-, and O K-edge regions and produced a much-improved X-ray absorption model of the ISM.

This poster will highlight some of the features of the srcflux script in CIAO. This script combines many threads and tools together to compute photometric properties for sources: counts, rates, various fluxes, and confidence intervals or upper limits. Beginning and casual X-ray astronomers greatly benefit from the simple interface: just specify the event file and a celestial location, while power-users and X-ray astronomy experts can take advantage of the all the parameters to automatically produce catalogs for entire fields. Current limitations and future enhancements of the script will also be presented.

Poster

Perhaps the best resolution that grazing incidence optics can achieve is 100 marcsec. Further improvement may be obtainable with a technology based on diffractive-refractive transmitting optics. The telescope would be light weight and inexpensive. However, the focal length is ~1000 km so mission operations are challenging. The optics and detector are aboard separate S/C. Aligning the two S/C and changing targets require propulsion engines. A low thrust engine, ~50 microN can neutralize gravity gradients to maintain the telescope-detector alignment. A higher thrust engine, ~50 miliN is needed to change targets within a time of 100,000 seconds. The large focal plane scale limits the field of view in practice to less than an arc second.

As the Advanced CCD Imaging Spectrometer (ACIS) on the Chandra X-ray Observatory enters its fifteenth year of operation on orbit, it continues to perform well and produce spectacular scientific results. The response of ACIS has evolved over the lifetime of the observatory due to radiation damage, molecular contamination and aging of the spacecraft in general. Here we present highlights from the instrument team's monitoring program and our expectations for the future of ACIS. While the radioactive decay of the ACIS calibration source has decreased its utility, it continues to provide valuable data on the health of the instrument. Performance changes on ACIS continue to be manageable, and do not indicate any limitations on ACIS lifetime.

Poster

Based on newly updated AtomDB v3.0, we will present our theoretical investigations of X-ray line Diagnostics and a couple of applications for some typical non-equilibrium ionization(NEI) plasmas in massive star binaries, stellar cluster winds and supernova remnants.

Poster

The effects of turbulence on the Thomson scattering process are investigated in turbulent plasmas by the scattering of electromagnetic waves. The Thomson scattering cross section in turbulent plasmas is obtained by the fluctuation-dissipation theorem and plasma dielectric function as a function of the diffusion coefficient, wave number, and Debye length. It is demonstrated that the turbulence effect suppresses the Thomson scattering cross section. It is also shown that the turbulence effect on the Thomson scattering process decreases with increasing thermal energy. The dependence of the wave number on the total Thomson scattering cross section including the turbulent structure factor is also discussed.

Sherpa is the CIAO modeling and fitting application. Sherpa evolved from an X-ray specific analysis package to a general-purpose fitting engine with advanced capabilities. Building and installing Sherpa as a standalone Python package was problematic, but starting from version 4.7 Sherpa does not depend on CIAO and can be built or installed as a standalone package. This is the first step towards migrating the Sherpa codebase to GitHub, so that a wider community can be engaged in its development. Sherpa will be available in binary form using the Conda package manager, as well as a source distribution. Advanced configurations for custom setups are supported. This new version of Sherpa can thus be easily used along with other python tools like ipython notebooks and astropy.

Poster

The first release of the Chandra data analysis system CIAO in the summer of 1999 enabled initial Chandra guest observer science. We continue to extend and improve the CIAO package, supporting both advanced use by experienced X-ray astronomers and simple analysis by novice users. Ongoing recent usability improvements include high level scripts to automate common, repetitive tasks and simplify the data reduction process, and improved support for merging observations that have been split due to thermal constraints. We present these improvements, discuss new documentation threads and present statistics on CIAO downloads and helpdesk usage.

The next generation of high-resolution X-ray grating spectra Abstract: We present the design and scientific motivation for Arcus, an X-ray grating spectrometer mission to be deployed on the International Space Station. This mission will observe structure formation at and beyond the edges of clusters and galaxies, feedback from supermassive black holes, the structure of the interstellar medium and the formation and evolution of stars. Key mission requirements will be R>2500 and >600 cm^2 of effective area at the crucial O VII and O VIII lines, with the full bandpass going from 8-52 Angstroms, with an overall minimum resolution of 1300 and effective area >150 cm^2. We will use the silicon pore optics proposed for ESAís Athena mission, paired with off-plane gratings being developed at the University of Iowa and combined with MIT/Lincoln Labs CCDs.

We describe a new calibration of the wavelength-dependent cross-dispersion profile of LETG/HRC-S spectra, which allows the use of a narrower spectral extraction region. Background is reduced by ~20% with negligible loss of X-ray signal. Some features of this work are improved 0th order positions, corrections for a fixed pattern of wiggles and slight time-dependent tilts in dispersed spectra, and an updated calibration of the enclosed energy fraction (EEFRAC) that includes the effects of asymmetric cross-dispersion profiles.

Poster

The Chandra Data Archive (CDA) has been serving the Chandra users community for 15 years. In this poster we will present some new CDA research tools and feature statistics showing how well the CDA is being used by the science community. We will also present plans for new products scheduled to be rolled out in the coming year.

Poster