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Full-Text Articles in Astrophysics and Astronomy
X-Ray Detected Active Galactic Nuclei In Dwarf Galaxies At 0 < Z < 1, K. Pardo, A. D. Goulding, J. E. Greene, R. S. Somerville, E. Gallo, R. C. Hickox
X-Ray Detected Active Galactic Nuclei In Dwarf Galaxies At 0 < Z < 1, K. Pardo, A. D. Goulding, J. E. Greene, R. S. Somerville, E. Gallo, R. C. Hickox
Dartmouth Scholarship
We present a sample of accreting supermassive black holes (SMBHs) in dwarf galaxies at z\lt 1. We identify dwarf galaxies in the NEWFIRM Medium Band Survey with stellar masses of {M}\star \lt 3× {10}9 {M}⊙ that have spectroscopic redshifts from the DEEP2 survey and lie within the region covered by deep (flux limit of ˜ 5× {10}-17{--}6× {10}-16 {erg} {{cm}}-2 {{{s}}}-1) archival Chandra X-ray data. From our sample of 605 dwarf galaxies, 10 exhibit X-ray emission consistent with that arising from active galactic nucleus (AGN) activity. If black-hole mass scales roughly …
Obscured Agns In Bulgeless Hosts Discovered By Wise : The Case Study Of Sdss J1224+5555, S. Satyapal, N. J. Secrest, B. Rothberg, J. A. O’Connor, S. L. Ellison, R. C. Hickox
Obscured Agns In Bulgeless Hosts Discovered By Wise : The Case Study Of Sdss J1224+5555, S. Satyapal, N. J. Secrest, B. Rothberg, J. A. O’Connor, S. L. Ellison, R. C. Hickox
Dartmouth Scholarship
There is mounting evidence that supermassive black holes form and grow in bulgeless galaxies. However, a robust determination of the fraction of AGNs in bulgeless galaxies, an important constraint to models of supermassive black hole seed formation and merger-free models of AGN fueling, is unknown, since optical studies have been shown to be incomplete for low mass AGNs. In a recent study using the Wide-field Infrared Survey Explorer, we discovered hundreds of bulgeless galaxies that display mid-infrared signatures of extremely hot dust suggestive of powerful accreting massive black holes, despite having no signatures of black hole activity at optical wavelengths. …
The Intrinsic Eddington Ratio Distribution Of Active Galactic Nuclei In Star-Forming Galaxies From The Sloan Digital Sky Survey, Mackenzie L. Jones, Ryan C. Hickox, Christine S. Black, Kevin N. Hainline, Michael A. Dipompeo, Andy D. Goulding
The Intrinsic Eddington Ratio Distribution Of Active Galactic Nuclei In Star-Forming Galaxies From The Sloan Digital Sky Survey, Mackenzie L. Jones, Ryan C. Hickox, Christine S. Black, Kevin N. Hainline, Michael A. Dipompeo, Andy D. Goulding
Dartmouth Scholarship
An important question in extragalactic astronomy concerns the distribution of black hole accretion rates of active galactic nuclei (AGNs). Based on observations at X-ray wavelengths, the observed Eddington ratio distribution appears as a power law, while optical studies have often yielded a lognormal distribution. There is increasing evidence that these observed discrepancies may be due to contamination by star formation and other selection effects. Using a sample of galaxies from the Sloan Digital Sky Survey Data Release 7, we test whether or not an intrinsic Eddington ratio distribution that takes the form of a Schechter function is consistent with previous …
A Tale Of Two Narrow-Line Regions: Ionization, Kinematics, And Spectral Energy Distributions For A Local Pair Of Merging Obscured Active Galaxies, Kevin N. Hainline, Ryan C. Hickox, Chien-Ting Chen, Christopher M. Carroll, Mackenzie L. Jones, Alexandros S. Zervos, Andrew D. Goulding
A Tale Of Two Narrow-Line Regions: Ionization, Kinematics, And Spectral Energy Distributions For A Local Pair Of Merging Obscured Active Galaxies, Kevin N. Hainline, Ryan C. Hickox, Chien-Ting Chen, Christopher M. Carroll, Mackenzie L. Jones, Alexandros S. Zervos, Andrew D. Goulding
Dartmouth Scholarship
We explore the gas ionization and kinematics, as well as the optical-IR spectral energy distributions for UGC 11185, a nearby pair of merging galaxies hosting obscured active galactic nuclei (AGNs), also known as SDSS J181611.72+423941.6 and J181609.37+423923.0 (J1816NE and J1816SW, z ≈ 0.04). Due to the wide separation between these interacting galaxies (~23 kpc), observations of these objects provide a rare glimpse of the concurrent growth of supermassive black holes at an early merger stage. We use BPT line diagnostics to show that the full extent of the narrow-line emission in both galaxies is photoionized by an AGN, and confirm …