88 citations · 263 across the 17 of their papers we have counts for
18 papers
Separating the Optical to Near-Infrared Light of AGN and Their Host Galaxies
Callum Dewsnap, Pauline Barmby, Sarah C. Gallagher
The properties of galaxies that host active galactic nuclei (AGNs) offer clues to the conditions that enable accretion onto supermassive black holes. A galaxy's morphology can prov…
Classifying Quasar Types Without a Spectrum
Adrien Hélias, Pauline Barmby, Sarah C. Gallagher +2
Distinguishing between Type 1 and Type 2 quasars is important because it helps us understand accretion regimes, black hole mass scaling, disk instabilities and feedback processes i…
JWST/NIRCam Coronagraphic Search for Hidden Planets in the HD~163296 Protoplanetary Disk
Taichi Uyama, Luca Ricci, Marie Ygouf +10
HD~163296 is a Herbig Ae/Be star with multiple signposts of on-going planet formation on its disk, such as prominent rings and gaps, as well as kinematic features as identified by…
Star Clusters in Tidal Debris
Michael Rodruck, Jane Charlton, Sanchayeeta Borthakur +13
We present results of a Hubble Space Telescope (HST) UBVI-band study of star clusters in tidal tails, using new WFC3 and ACS imaging to complement existing WFPC2 data. We survey 12…
X-Rays Beware: The Deepest Chandra Catalogue of Point Sources in M31
N. Vulic, S. C. Gallagher, P. Barmby
This study represents the most sensitive Chandra X-ray point source catalogue of M31. Using 133 publicly available Chandra ACIS-I/S observations totalling ~1 Ms, we detected 795 X-…
Exploring X-ray Binary Populations in Compact Group Galaxies with
P. Tzanavaris, A. E. Hornschemeier, S. C. Gallagher +5
We obtain total galaxy X-ray luminosities, , originating from individually detected point sources in a sample of 47 galaxies in 15 compact groups of galaxies (CGs). For the gr…
Investigating the Structure of the Windy Torus in Quasars
S. C. Gallagher, J. E. Everett, M. M. Abado +1
Thermal mid-infrared emission of quasars requires an obscuring structure that can be modeled as a magneto-hydrodynamic wind in which radiation pressure on dust shapes the outflow.…
Faint X-ray Binaries and Their Optical Counterparts in M31
N. Vulic, S. C. Gallagher, P. Barmby
X-ray binaries (XRBs) are probes of both star formation and stellar mass, but more importantly remain one of the only direct tracers of the compact object population. To investigat…
A View of Point Sources in Hickson Compact Groups: High AGN fraction but a dearth of strong AGNs
P. Tzanavaris, S. C. Gallagher, A. E. Hornschemeier +6
We present X-ray point source catalogs for 9 Hickson Compact Groups (HCGs, 37 galaxies) at distances Mpc. We perform detailed X-ray point source detection and p…
High Signal-to-Noise Ratio Mid-Infrared Quasar Spectral Templates
Allison R. Hill, S. C. Gallagher, R. P. Deo +2
Mid-infrared (MIR) quasar spectra exhibit a suite of emission features including high ionization coronal lines from the narrow line region (NLR) illuminated by the ionizing continu…
Characterizing Quasars in the Mid-infrared: High Signal-to-Noise Spectral Templates
Allison R. Hill, S. C. Gallagher, R. P. Deo +2
Mid-infrared (MIR) quasar spectra exhibit a suite of emission features including high ionization coronal lines from the narrow line region illuminated by the ionizing continuum, br…
Why a Windy Torus?
S. C. Gallagher, M. M. Abado, J. E. Everett +2
Mass ejection in the form of winds or jets appears to be as fundamental to quasar activity as accretion, and can be directly observed in many objects with broadened and blue-shifte…
Stacking Star Clusters in M51: Searching for Faint X-Ray Binaries
N. Vulic, P. Barmby, S. C. Gallagher
The population of low-luminosity (< 10^35 erg/s) X-Ray Binaries (XRBs) has been investigated in our Galaxy and M31 but not further. To address this problem, we have used data from…
The Long-Term X-Ray Variability of Broad Absorption Line Quasars
Cristian Saez, William N. Brandt, Sarah C. Gallagher +2
We analyze the long-term (rest-frame 3-30 yr) X-Ray variability of eleven broad absorption line (BAL) quasars, mainly to constrain the variation properties of the X-Ray absorbing s…
Looking for the Wind in the Dust
S. C. Gallagher, J. E. Everett, S. K. Keating +2
The blue-shifted broad emission lines and/or broad absorption lines seen in many luminous quasars are striking evidence for a broad line region in which radiation driving plays an…
The merger history, AGN and dwarf galaxies of Hickson Compact Group 59
I. S. Konstantopoulos, S. C. Gallagher, K. Fedotov +16
Compact group galaxies often appear unaffected by their unusually dense environment. Closer examination can, however, reveal the subtle, cumulative effects of multiple galaxy inter…
Star Clusters as Tracers of Interactions in Stephan's Quintet (Hickson Compact Group 92)
K. Fedotov, S. C. Gallagher, I. S. Konstantopoulos +5
Stephan's Quintet (SQ) is a compact group of galaxies that exhibits numerous signs of interactions between its members. Using high resolution images of SQ in B438, V606, and I814 b…
Hubble Space Telescope Images of Stephan's Quintet: Star Cluster Formation in a Compact Group Environment
S. C. Gallagher, J. C. Charlton, S. D. Hunsberger +2
Analysis of Hubble Space Telescope/Wide Field Planetary Camera 2 images of Stephan's Quintet, Hickson Compact Group 92, yielded 115 candidate star clusters (with V-I < 1.5). Unlike…