Publications (134)
The faint X-ray Source Population near 3C 295
Valerio D'Elia, Fabrizio Fiore, Martin Elvis +5
We present a statistical analysis of the Chandra observation of the source field around the 3C 295 galaxy cluster (z=0.46) aimed at the search for clustering of X-ray sources. We a…
Black Hole Growth & the M_BH--Bulge Relations
Smita Mathur, Dirk Grupe
We present the black hole mass--bulge velocity dispersion relation for a complete sample of 75 soft X-ray selected AGNs. We find that the AGNs with highest accretion rates relative…
Recent Chandra Results on AGNs & Future Prospects
Smita Mathur
I review Chandra's achievements in the last two years in AGN research. I concentrate on some topics of my interest; some others are reviewed in an accompanying article by K. Nandra…
The z=5.8 Quasar SDSSp J1044-0125: A Peek at Quasar Evolution?
Smita Mathur
The newly discovered z=5.8 quasar SDSSp J104433.04-012502.2 was recently detected in X-rays and found to be extremely X-ray weak. Here we present the hardness ratio analysis of the…
Missing Baryons and the Warm-Hot Intergalactic Medium
F. Nicastro, Smita Mathur, Martin Elvis
Stars and gas in galaxies, hot intracluster medium, and intergalactic photo-ionized gas make up at most half of the baryons that are expected to be present in the universe. The maj…
Narrow-line Seyfert 1 Galaxies from the Sloan Digital Sky Survey Early Data Release
Rik J. Williams, Richard W. Pogge, Smita Mathur
We present a sample of 150 narrow-line Seyfert 1s (NLS1s) found within the Sloan Digital Sky Survey Early Data Release (EDR), only two of which were previously identified as such.…
Detection of high velocity outflows in Seyfert 1 galaxy Mrk 590
Anjali Gupta, Smita Mathur, Yair Krongold
We report on the detection of ultra-fast outflows in the Seyfert~1 galaxy Mrk 590. These outflows are identified through highly blue-shifted absorption lines of OVIII and NeIX in t…
Low-Level Nuclear Activity in Nearby Spiral Galaxies
Himel Ghosh, Smita Mathur, Fabrizio Fiore +1
We are conducting a search for supermassive black holes (SMBHs) with masses below 10^7 M_sun by looking for signs of extremely low-level nuclear activity in nearby galaxies that ar…
Broad Absorption Line QSOs Observed by the ROSAT PSPC
Paul J. Green, Smita Mathur
Recent results from the ROSAT All-Sky Survey (RASS) have shown that broad absorption line (BAL) QSOs are either highly absorbed or underluminous in the soft X-ray bandpass. Here, w…
Strong X-ray Absorption in a BALQSO: PHL5200
Smita Mathur, Martin Elvis, K. P. Singh
We present observations of the z=1.98 prototype BALQSO: PHL5200. The source was detected in both SIS and GIS. A power-law spectrum () with la…
Chandra and Far Ultraviolet Spectroscopic Explorer Observations of z~0 Warm-Hot Gas Toward PKS 2155-304
Rik J. Williams, Smita Mathur, Fabrizio Nicastro +1
The X-ray bright z=0.116 quasar PKS 2155-304 is frequently observed as a Chandra calibration source, with a total of 483 ksec of Low Energy Transmission Grating (LETG) exposure tim…
Detection of 'super-virial' gas in the Circumgalactic medium of the Milky Way towards PKS 2155-304
Mukesh Singh Bisht, Sanskriti Das, Smita Mathur +3
We present the first simultaneous detection of four distinct highly ionized absorbing phases using Chandra and XMM-Newton grating spectra toward the blazar PKS 2155…
Constraining the Sub-Galactic Relationship Between Star Formation and the Hot Interstellar Medium in NGC 4254
Erik B. Monson, Bret D. Lehmer, Amirnezam Amiri +17
We investigate the relationship between star formation and X-ray emission from the hot interstellar medium (ISM) on kpc scales in NGC 4254 (M99) by combining spatially resolv…
Lost Baryons at Low Redshift
Smita Mathur, Fabrizio Nicastro, Rik J. Williams
We review our attempts to discover lost baryons at low redshift with ``X-ray forest'' of absorption lines from the warm-hot intergalactic medium. We discuss the best evidence to da…
Probing the Warm-Hot Circumgalactic Medium with broad OVI and X-rays
Smita Mathur, Anjali Gupta, Sanskriti Das +2
Most of the baryonic mass in the circumgalactic medium (CGM) of a spiral galaxy is believed to be warm-hot, with temperature around K. The narrow OVI absorption lines probe a…
GALEX Measurements of the Big Blue Bump in Soft X-ray Selected AGN
David W. Atlee, Smita Mathur
We study the UV properties of Type I AGN from the ROSAT All-Sky Survey that have been selected to show unusually soft X-ray continua. We examine a sample of 54 Seyfert 1 galaxies w…
Revisiting the Black Hole Masses of Soft X-ray-Selected Active Galactic Nuclei
Linda C. Watson, Smita Mathur, Dirk Grupe
In our previous work, using luminosity and the H-beta FWHM as surrogates for black hole mass (M_BH), we compared the black hole masses of narrow-line Seyfert 1 galaxies (NLS1s) and…
Time-Evolving Photoionization: the Thin and Compact X-Ray Wind of NGC 4051
Fabrizio Nicastro, Yair Krongold, Martin Elvis +3
We discuss the power of time-evolving photoionization as a diagnostic tool to measure the electron density of photoionized gas. We apply this technique to a XMM-Newton observation…
Tracing the Warm-Hot Intergalactic Medium at Low Redshift: X-ray Forest Observations Towards H1821+643
Smita Mathur, David Weinberg, Xuelei Chen +1
We present a high resolution (R~500) X-ray spectrum of the bright quasar H1821+643 (z=0.297), obtained in a 470 ksec Chandra observation. We search for X-ray absorption by highly i…
Stringent constraints on the H I spin temperature in two z > 3 Damped Lyman-alpha systems from redshifted 21 cm absorption studies
Nirupam Roy, Smita Mathur, Vishal Gajjar +1
Physical properties of Damped Lyman-alpha absorbers and their evolution are closely related to galaxy formation and evolution theories, and have important cosmological implications…
Black hole growth by accretion
Smita Mathur, Dirk Grupe
We show that black holes grow substantially by accretion at close to Eddington rates. Using a complete sample of soft X-ray selected AGNs, Grupe & Mathur (2004) have shown that nar…
The Ionized Gas and Nuclear Environment in NGC 3783 II. Averaged HST/STIS and FUSE Spectra
Jack R. Gabel, D. Michael Crenshaw, Steven B. Kraemer +14
We present observations of the intrinsic absorption in the Seyfert 1 galaxy NGC 3783 obtained with the STIS/HST and FUSE. We have coadded multiple STIS and FUSE observations to obt…
The LeMMINGs survey: probing sub-kpc radio structures of nearby galaxies with e-MERLIN
David R. A. Williams, Ranieri D. Baldi, Robert J. Beswick +10
The Legacy e-MERLIN Multi-band Imaging of Nearby Galaxies survey (LeMMINGs) is a statistically-complete census of nuclear accretion and star formation processes in the local Univer…
Chandra Detection of Highest Redshift (z~6) Quasars in X-rays
Smita Mathur, Belinda Wilkes, Himel Ghosh
We report on Chandra observations of three quasars SDSSP J083643+005453, SDSSP J103027+052455, and SDSSP J130608+035626 at redshifts 5.82, 6.28 and 5.99 respectively. All the three…
Finding Local Low-mass Supermassive Black Holes
Smita Mathur, Himel Ghosh, Laura Ferrarese +1
The low-mass end of the supermassive black hole mass function is unknown and difficult to determine. Here we discuss our successful program to find active nuclei of late type "norm…
Suzaku Monitoring of the Iron K Emission Line in the Type 1 AGN NGC 5548
Yuan Liu, Martin Elvis, Ian M. McHardy +10
We present 7 sequential weekly observations of NGC 5548 conducted in 2007 with the \textit{Suzaku} X-ray Imaging Spectrometer (XIS) in the 0.2-12 keV band and Hard X-ray Detector (…
Hot Gas Outflow Properties of the Starburst Galaxy NGC 4945
Natalia Porraz Barrera, Sebastian Lopez, Laura A. Lopez +5
We analyze 330 ks of {\it Chandra} X-ray imaging and spectra of the nearby, edge-on starburst and Seyfert Type 2 galaxy NGC 4945 to measure the hot gas properties along the galacti…
Where is the Supervirial hot gas? I: A pilot study with sightlines to Galactic X-ray binaries
Armando Lara-DI, Yair Krongold, Smita Mathur +4
Hot, \logT\ 7.5, gas was recently discovered in the Milky Way in extragalactic sightlines. In order to determine its location, here we present sightlines to Galactic X-ray b…
Empirical estimates of the Galactic halo contribution to the dispersion measures of extragalactic fast radio bursts using X-ray absorption
Sanskriti Das, Smita Mathur, Anjali Gupta +2
We provide an empirical list of the Galactic dispersion measure () contribution to the extragalactic fast radio bursts along 72 sightlines. It is independent of any model…
On the origin of the K hot emitting gas in the Circumgalactic medium of the Milky Way
Mukesh Singh Bisht, Biman B. Nath, Smita Mathur
The presence of the K gas in the circumgalactic medium of the Milky Way has been well established. However, the location and the origin of the newly discovered hot g…
Hubble Space Telescope Ultraviolet Spectroscopy of Fourteen Low-Redshift Quasars
Rajib Ganguly, Michael S. Brotherton, Nahum Arav +35
We present low-resolution ultraviolet spectra of 14 low redshift (z<0.8) quasars observed with HST/STIS as part of a Snap project to understand the relationship between quasar outf…
Observations of the gamma-ray emitting narrow-line Seyfert 1, SBS 0846+513, and its host galaxy
Timothy S. Hamilton, Marco Berton, Sonia Antón +9
The gamma-ray emitting galaxy SBS 0846+513 has been classified as a Narrow-Line Seyfert 1 from its spectroscopy, and on that basis it was thought likely to have a small central bla…
The Composite Spectrum of Strong Lyman-alpha Forest Absorbers
Matthew M. Pieri, Stephan Frank, David H. Weinberg +2
We present a new method for probing the physical conditions and metal enrichment of the Intergalactic Medium: the composite spectrum of Ly-alpha forest absorbers. We apply this tec…
Chandra Observations of X-ray Weak Narrow-Line Seyfert 1 Galaxies
Rik J. Williams, Smita Mathur, Richard W. Pogge
We present Chandra observations of 17 optically-selected, X-ray weak narrow-line Seyfert 1 (NLS1) galaxies. These objects were optically identified by Williams et al. (2002) in the…
The candidate filament close to the 3C295 galaxy cluster: optical and X-ray spectroscopy
Valerio D'Elia, Fabrizio Fiore, Smita Mathur +1
We present a detailed analysis of the overdensity of X-ray sources colse to the 3C 295 galaxy cluster (z=0.46) to assess whether it is associated with a filament of the large-scale…
Probing the Local Group Medium Toward Mkn 421 with Chandra and FUSE
Rik J. Williams, Smita Mathur, Fabrizio Nicastro +7
We report the detection of highly-ionized gas at z~0 seen in resonant UV and X-ray absorption lines toward the z=0.03 blazar Mkn 421. A total of 13 X-ray and 3 UV lines were measur…
Thermal Structure and Chemical Enrichment of the North and South Polar Spurs: Supersolar N/O and Ne/O in the X-ray Plasma
Anjali Gupta, Smita Mathur, Joshua Kingsbury +5
The North Polar Spur (NPS) is a prominent diffuse X-ray feature whose origin has remained uncertain for decades. Using a uniform analysis of archival \textit{Suzaku} and \textit{XM…
Detection of the diffuse HI emission in the Circumgalactic Medium of NGC 891 and NGC 4565
Sanskriti Das, Amy Sardone, Adam K. Leroy +5
We present detections of 21-cm emission from neutral hydrogen (HI) in the circumgalactic medium (CGM) of the local edge-on galaxies NGC 891 and NGC 4565 using the Robert C. Byrd Gr…
A Chandra Survey of Broad Absorption Line Quasars
Paul J. Green, Thomas L. Aldcroft, Smita Mathur +2
We have carried out a survey with the Chandra X-ray Observatory of a sample of 10 optically bright broad absorption line (BAL) QSOs. Eight out of ten sources are detected. The 6 br…
Warm Absorbers in Active Galactic Nuclei
Smita Mathur
Observations of warm absorbers provided new ways to study the nuclear environments of AGNs. I discuss basic properties of warm absorbers and early developments with ROSAT, ASCA and…
Evolution of Active Galaxies: Black-hole Mass - Bulge relations for Narrow Line Objects
Smita Mathur, Joanna Kuraszkiewicz, Bozena Czerny
Mathur (2000) has proposed that the narrow line Seyfert 1 galaxies (NLS1s) are likely to be the active galaxies in early stage of evolution. To test this hypothesis, we have calcul…
Detection of diffuse HI emission in the circumgalactic medium of NGC891 and NGC4565 -- II
Sanskriti Das, Mary Rickel, Adam Leroy +6
We probe the neutral circumgalactic medium (CGM) along the major axes of NGC891 and NGC4565 in 21-cm emission out to kpc using the Green Bank Telescope (GBT), extendin…
Where is the Supervirial Gas? III. Insights from X-ray Shadow Observations and a revised Model for the Soft Diffuse X-ray Background
Anjali Gupta, Smita Mathur, Joshua Kingsbury +5
Shadow observations provide a powerful tool to separate foreground components of the soft diffuse X-ray background (SDXB) from the background components. Such observations have now…
Discovery of Associated Absorption Lines in an X-ray Warm Absorber: HST Observations of PG1114+445
Smita Mathur, Belinda Wilkes, Martin Elvis
The unified picture of X-ray/UV absorbers offers an unique opportunity to probe the nuclear environment of AGNs. To test the unified absorber scenario and to understand the physica…
The Compact, Conical, Accretion-Disk Warm Absorber of the Seyfert 1 Galaxy NGC 4051 and its Implications for IGM-Galaxy Feedback Processes
Yair Krongold, Fabrizio Nicastro, Martin Elvis +4
(Abridged) Using a 100 ks XMM-Newton exposure of NGC 4051, we show that the time evolution of the ionization state of the X-ray absorbers in response to the rapid and highly variab…
Metallicity measurements in AGNs
Smita Mathur, Dale Fields
Measuring metallicity in the nuclear regions of AGNs is difficult because only a few lines are observed and ionization correction becomes a major problem. Nitrogen to carbon ratio…
NGC 7582: The Prototype Narrow-Line X-ray Galaxy
Jonathan F. Schachter, Fabrizio Fiore, Martin Elvis +5
NGC 7582 is a candidate prototype of the Narrow Line X-ray Galaxies (NLXGs) found in deep X-ray surveys. An ASCA observation shows the hard (> 3 keV) X-ray continuum of NGC 7582 dr…
The warm-hot gaseous halo of the Milky Way
Smita Mathur
The circumgalactic region of the Milky Way contains a large amount of gaseous mass in the warm-hot phase. The presence of this warm-hot halo observed through X-ray absorption…
Where is the Super-Virial Gas? The Supply from hot inflows
Manami Roy, Kung-Yi Su, Smita Mathur +1
In an effort to understand the presence of super-virial gas detected in the Milky Way, we present our findings from isolated galaxy simulations of Milky Way-like systems using GIZM…
Evidence for massive warm-hot circumgalactic medium around NGC 3221
Sanskriti Das, Smita Mathur, Anjali Gupta +3
We report a 3.4 detection of the warm-hot, massive, extended circumgalactic medium (CGM) around an L star-forming spiral galaxy NGC 3221, using deep Suzaku observations…
Black Hole Masses of Intermediate-Redshift Quasars: Near Infrared Spectroscopy
Matthias Dietrich, Smita Mathur, Dirk Grupe +1
We present near-infrared spectra of ten luminous, intermediate redshift quasars observed with SofI at the NTT of ESO/La Silla. With these rest-frame optical spectra we probe the Hb…
Measured Cosmological Mass Density in the WHIM: the Solution to the 'Missing Baryons' Problem
Fabrizio Nicastro, Martin Elvis, Fabrizio Fiore +1
We review the current high-significance X-ray detections of Warm-Hot Intergalactic Medium (WHIM) filaments at z>0 along the lines of sight to the two blazars Mrk 421 (z=0.03) and 1…
Detection of a Super-Virial Hot Component in the Milky Way Circumgalactic Medium Along Multiple Sight-Lines by Using the Stacking Technique
Armando Lara-DI, Smita Mathur, Yair Krongold +2
The study of the elusive hot component ( K) of the Milky Way circumgalactic medium (CGM) is a novel topic to understand Galactic formation and evolution. In this wo…
Deep X-ray observation of NGC 3221: everything everywhere all at once
Sanskriti Das, Smita Mathur, Bret D. Lehmer +3
We present a comprehensive analysis of 475 ks (438 ks unpublished & 37 ks archival) XMM-Newton/EPIC-pn observation of a nearby, highly inclined, star-forming, luminous infrared gal…
Thermal Sunyaev-Zel'dovich Effect in the circumgalactic medium -- II: dependence on star formation
Sanskriti Das, Nhut Truong, Yi-Kuan Chiang +1
We measure thermal Sunyaev-Zel'dovich (tSZ) Effect in the circumgalactic medium (CGM) of 2.5 million = WISEDESI galaxies out…
Galactic Corona or Local Group Intergalactic Medium?
Rik J. Williams, Smita Mathur, Fabrizio Nicastro
Cosmological hydrodynamic simulations predict that the low redshift universe comprises a web of warm-hot intergalactic gas and galaxies, with groups of galaxies and clusters formin…
Chandra Observations of Candidate "True" Seyfert 2 Nuclei
Himel Ghosh, Richard W. Pogge, Smita Mathur +2
The Unification Model for active galactic nuclei posits that Seyfert 2s are intrinsically like Seyfert 1s, but that their broad-line regions (BLRs) are hidden from our view. A Seyf…
Discovery of a Large Population of Ultraluminous X-ray Sources in the Bulge-less Galaxies NGC 337 and ESO 501-23
Garrett Somers, Smita Mathur, Paul Martini +3
We have used Chandra observations of eight bulge-less disk galaxies to identify new ultraluminous X-ray source (ULX) candidates, study their high mass X-ray binary (HMXB) populatio…
The X-ray Warm Absorber in NGC3516
Smita Mathur, Belinda J. Wilkes, Thomas Aldcroft
The Seyfert 1 galaxy, NGC3516 has been the subject of many absorption line studies at both ultraviolet and X-ray wavelengths. In the UV, strong, broad, variable associated metal li…
A Search for Oxygen in the Low-Density Lyman-alpha Forest Using the Sloan Digital Sky Survey
Matthew M. Pieri, Stephan Frank, Smita Mathur +3
We use 2167 Sloan Digital Sky Survey (SDSS) quasar spectra to search for low-density oxygen in the Intergalactic Medium (IGM). Oxygen absorption is detected on a pixel-by-pixel bas…
Discovery of Nuclear X-ray Sources in SINGS Galaxies
Catherine J. Grier, Smita Mathur, Himel Ghosh +1
We present the results of a search for nuclear X-ray activity in nearby galaxies using Chandra archival data in a sample of 62 galaxies from the Spitzer Infrared Nearby Galaxy Surv…
The Locus of Highly Accreting AGNs on the M_BH--sigma Plane: Selections, Limitations, and Implications
Smita Mathur, Dirk Grupe
We re-examine the locus of narrow line Seyfert 1 galaxies on the M_BH--sigma (black hole mass--bulge velocity dispersion) plane in the light of the results from large new optically…
Chandra Detection of Local Warm-Hot Gas Toward Markarian 279
Rik J. Williams, Smita Mathur, Fabrizio Nicastro
We report the Chandra detection of OVII Kαabsorption at z=0 in the direction of the z=0.03 Seyfert 1 galaxy Mkn 279. The high velocity cloud Complex C lies along this line of sigh…
XMM-Newton View of the Multi-Phase Warm Absorber in Seyfert 1 Galaxy NGC985
Yair Krongold, Elena Jimenez-Bailon, Maria Santos-Lleo +6
We present an analysis of an XMM-Newton observation of the Seyfert 1 Galaxy NGC 985. The EPIC spectra present strong residuals to a single power-law model, indicating the presence…
On the nature of the z=0 X-ray absorbers: II. The contrast between local and AGN host galaxy absorption
Rik J. Williams, Smita Mathur, Fabrizio Nicastro
We search for highly-ionized gas near three AGN host galaxies using the Chandra low-energy transmission grating spectrograph. Strong absorption lines from such gas are seen at z=0,…
Detection of thermal Sunyaev-Zel'dovich Effect in the circumgalactic medium of low-mass galaxies -- a surprising pattern in self-similarity and baryon sufficiency
Sanskriti Das, Yi-Kuan Chiang, Smita Mathur
We report on the measurement of the thermal Sunyaev-Zel'dovich (tSZ) Effect in the circumgalactic medium (CGM) of 641,923 galaxies with = at…
On the faint end of the high redshift AGN luminosity function
Francesco Shankar, Smita Mathur
Using the results of recent optical surveys we conclude that the {\it non}-detection of quasars down to faint magnitudes implies a significant flattening of the high redshift (z~6)…
Demography of high redshift AGN
Fabrizio Fiore, Simonetta Puccetti, Smita Mathur
High redshift AGN holds the key to understand the early structure formation and to probe the Universe during its infancy. We review the latest searches for high-z AGN in the deepes…
Temperature and Metallicity Gradients in the Hot Gas Outflows of M82
Laura A. Lopez, Smita Mathur, Dustin D. Nguyen +2
We utilize deep Chandra X-ray Observatory imaging and spectra of M82, the prototype of a starbursting galaxy with a multiphase wind, to map the hot plasma properties along the mino…
On Odd Radio Circles as Supernova Remnants
Sumit K. Sarbadhicary, Todd A. Thompson, Laura A. Lopez +1
The origin of arcmin-sized Odd Radio Circles (ORCs) found in modern all-sky radio surveys remain uncertain, with explanations ranging from starburst/AGN-driven shocks to supernova…
Super-virial Hot Phase in Milky Way Circumgalactic Medium: Further Evidences
Rebecca McClain, Smita Mathur, Sanskriti Das +2
Recent discoveries of a super-virial hot phase of the Milky Way circumgalactic medium (CGM) has launched new questions regarding the multi-phase structure of the CGM around the Gal…
Associated Absorption at Low and High Redshift
Martin Elvis, Smita Mathur, Belinda J. Wilkes +4
Combining information on absorbing material in AGN from X-ray and the UV creates a powerful investigative tool. Here we give examples from both low and high redshift.
The NGC 3341 minor merger: a panchromatic view of the active galactic nucleus in a dwarf companion
Stefano Bianchi, Enrico Piconcelli, Miguel Ãngel Pérez-Torres +4
We present X-ray (Chandra), radio (EVLA and EVN), and archival optical data of the triple-merging system in NGC3341. Our panchromatic analysis confirms the presence of a Seyfert 2…
Flares in the changing look AGN Mrk 590. I: The UV response to X-ray outbursts suggests a more complex reprocessing geometry than a standard disk
Daniel Lawther, Marianne Vestergaard, Sandra Raimundo +5
Mrk 590 is a known changing-look AGN which almost turned off in 2012, and then in 2017 partially re-ignited into a repeat flaring state, unusual for an AGN. Our \emph{Swift} observ…
Probing the Circumgalactic Medium at High-Redshift Using Composite BOSS Spectra of Strong Lyman-alpha Forest Absorbers
Matthew M. Pieri, Michael J. Mortonson, Stephan Frank +17
We present composite spectra constructed from a sample of 242,150 Lyman-alpha (Lya) forest absorbers at redshifts 2.4<z<3.1 identified in quasar spectra from the Baryon Oscillation…
Super-solar Metallicity in the NLS1 Galaxy Markarian 1044
Dale L. Fields, Smita Mathur, Richard W. Pogge +3
The determination of the bulk metallicity and the abundance mixture of various elements is very difficult in quasars and AGNs because only a few lines are observed and the ionizati…
Hidden Gems on a Ring: Infant Massive Clusters and Their Formation Timeline Unveiled by ALMA, HST, and JWST in NGC 3351
Jiayi Sun, Hao He, Kyle Batschkun +38
We study young massive clusters (YMCs) in their embedded "infant" phase with ALMA, HST, and JWST observations targeting the central starburst ring in NGC…
Agnostic Stacking of Intergalactic Doublet Absorption: Measuring the NeVIII Population
Stephan Frank, Matthew M. Pieri, Smita Mathur +2
We present a blind search for doublet intergalactic metal absorption with a method dubbed `agnostic stacking'. Using a forward-modelling framework we combine this with direct detec…
Synergistic Astrophysics in the Ultraviolet using Active Galactic Nuclei
Gerard Kriss, Nahum Arav, Anton Koekemoer +3
Observing programs comprising multiple scientific objectives will enhance the productivity of NASA's next UV/Visible mission. Studying active galactic nuclei (AGN) is intrinsically…
Chandra Detection of the First X-ray Forest along the Line of Sight To Mkn 421
Fabrizio Nicastro, Smita Mathur, Martin Elvis +7
We present the first >=3.5 sigma (conservative) or >=5.8 sigma (sum of lines significance) detection of two Warm-Hot Intergalactic Medium (WHIM) filaments at z>0, which we find alo…
A Spitzer-MIPS search for dust in compact high-velocity HI clouds
Rik J. Williams, Smita Mathur, Shawn Poindexter +2
We employ three-band Spitzer-MIPS observations to search for cold dust emission in three neutral hydrogen compact high-velocity clouds (CHVCs) in the vicinity of the Milky Way. Far…
Resolved HII regions in NGC 253: Ionized gas structure and suggestions of a universal density-surface brightness relation
Rebecca L. McClain, Adam K. Leroy, Enrico Congiu +23
We use the full-disk VLT-MUSE mosaic of NGC 253 to identify 2492 HII regions and study their resolved structure. With an average physical resolution of 17 pc, this is one of the la…
Detecting Low-Mass Supermassive Black Holes
Himel Ghosh, Smita Mathur, Fabrizio Fiore +1
We demonstrate the feasibility of uncovering supermassive black holes in late-type, quiescent spiral galaxies by detecting signs of very low-level nuclear activity. We use a combin…
BeppoSAX Observations of the Maser Sy2 Galaxy: ESO103-G35
Belinda J. Wilkes, Smita Mathur, Fabrizio Fiore +2
We have made BeppoSAX observations of the Seyfert 2/1.9 galaxy ESO103-G35, which contains a nuclear maser source and is known to be heavily absorbed in the X-rays. Analysis of the…
Variable X-ray Absorption toward Gravitationally-Lensed Blazar PKS1830-211
Xinyu Dai, Smita Mathur, George Chartas +2
We present X-ray spectral analysis of five Chandra and XMM-Newton observations of the gravitationally-lensed blazar PKS1830-211 from 2000 to 2004. We show that the X-ray absorption…
X-ray Properties of NGC 253's Starburst-Driven Outflow
Sebastian Lopez, Laura A. Lopez, Dustin D. Nguyen +5
We analyze image and spectral data from 365~ks of observations from the {\it Chandra} X-ray Observatory of the nearby, edge-on starburst galaxy NGC 253 to constrain proper…
UV counterpart of an X-ray ultra-fast outflow in IRAS 17020+4544
Missagh Mehdipour, Gerard A. Kriss, Yair Krongold +7
We report on the discovery of a UV absorption counterpart of a low-ionization X-ray ultra-fast outflow (UFO) in the Narrow-Line Seyfert-1 galaxy IRAS 17020+4544. This UV signature…
XMM-Newton Observations of Three Interacting Luminous Infrared Galaxies
Dale Mudd, Smita Mathur, Matteo Guainazzi +8
We investigate the X-ray properties of three interacting luminous infrared galaxy systems. In one of these systems, IRAS 18329+5950, we resolve two separate sources. A second, IRAS…
NGC 5548: Lack of a Broad Fe K Line and Constraints on the Location of the Hard X-ray Source
Laura Brenneman, Martin Elvis, Yair Krongold +2
We present an analysis of the co-added and individual 0.7-40 keV spectra from seven Suzaku observations of the Sy 1.5 galaxy NGC 5548 taken over a period of eight weeks. We conclud…
Super-solar N/C in the NLS1 Galaxy Markarian 1044
Dale L. Fields, Smita Mathur, Richard W. Pogge +2
Narrow-Line Seyfert 1s (NLS1s) are known to have extreme values of a number of properties compared to Active Galactic Nuclei (AGN) as a class. In particular, previous emission-line…
Supermassive black holes, pseudobulges, and the narrow-line Seyfert 1 galaxies
Smita Mathur, Dale Fields, Bradley M. Peterson +1
We present HST/ACS observations of ten galaxies that host narrow-line Seyfert 1 (NLS1) nuclei, believed to contain relatively smaller mass black holes accreting at high Eddington r…
The weak absorbing outflow in AGN Mrk 279: evidence of super-solar metal abundances
Dale L. Fields, Smita Mathur, Yair Krongold +2
We present analysis and photoionization modeling of the Chandra high resolution spectrum of Mrk 279. There is clear evidence of an absorbing outflow which is best fit by a two comp…
Chandra discovery of the intracluster medium around UM425 at redshift 1.47
Smita Mathur, Rik J. Williams
We report on a discovery of a candidate cluster of galaxies at redshift z=1.47 based on Chandra observations in the field of quasars UM425 A & B. We detect with high significance d…
Probing the hot circumgalactic medium of external galaxies in X-ray absorption II: a luminous spiral galaxy at
Smita Mathur, Sanskriti Das, Anjali Gupta +1
The circumgalactic medium (CGM) is the most massive baryonic component of a spiral galaxy, shock heated to about K for an galaxy. The CGM of the Milky Way has…
Spiral Galaxies as Progenitors of Pseudobulge Hosting S0s
Kaustubh Vaghmare, Sudhanshu Barway, Smita Mathur +1
We present observations of pseudobulges in S0 and spiral galaxies using imaging data taken with the Spitzer Infra-Red Array Camera. We have used 2-d bulge-disk-bar decomposition to…
Comments On The Intrinsic X-ray/UV Absorbers In AGN
Smita Mathur
This talk discusses the unified X-ray/UV absorption models in AGN. I will first review the models and discuss how they offer an unique opportunity to probe the near nuclear environ…
The warm-hot, extended, massive circumgalactic medium of NGC 3221: an XMM-Newton discovery
Sanskriti Das, Smita Mathur, Anjali Gupta
Using Suzaku data, we had found a evidence for the X-ray emitting warm-hot circumgalactic medium (CGM) in the L galaxy NGC 3221. Here we present XMM-Newton data and…
Super-virial temperature or Neon overabundance?: Suzaku observations of the Milky Way circumgalactic Medium
Anjali Gupta, Joshua Kingsbury, Smita Mathur +4
We analyzed Suzaku and Chandra observations of the soft diffuse X-ray background toward four sightlines with the goal of characterizing the X-ray emission from the Milky Way circum…
Supersolar metal abundances and the Broad Line Region of Narrow-line Seyfert 1 galaxies
Stefanie Komossa, Smita Mathur
Narrow-line Seyfert 1 galaxies (NLSy1) are intriguing due to their extreme continuum and emission line properties which are not yet well understood. This paper is motivated by the…
Probing The Dust-To-Gas Ratio of z > 0 Galaxies Through Gravitational Lenses
Xinyu Dai, Christopher S. Kochanek, George Chartas +1
We report the detection of differential gas column densities in three gravitational lenses, MG0414+0534, HE1104-1805, and PKS1830-211. Combined with the previous differential colum…