Browsing by Author "Koss, M."
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- ItemA model for AGN variability on multiple time-scales.(2018) Sartori, Lia F.; Treister, Ezequiel; Schawinski, Kevin; Trakhtenbrot, Benny; Caplar, Neven; Koss, M.; Urry, Claudia Megan; Zhang, Ce
- ItemA New Compton-thick AGN in Our Cosmic Backyard: Unveiling the Buried Nucleus in NGC 1448 with NuSTAR(2017) Annuar, A.; Alexander, D.; Gandhi, P.; Lansbury, G.; Asmus, D.; Ballantyne, D.; Bauer, Franz Erik; Boggs, S.; Boorman, P.; Brandt W.; Brightman, M.|Christensen, F.; Craig, W.; Farrah, D.; Goulding, A.; Hailey, C.; Harrison, F.; Koss, M.; Lamassa, S.; Murray, S.; Ricci, Claudio; Rosario, D.; Stanley, F.; Stern, D.; Zhang, W.
- ItemA new population of compton-thick AGNs identified using the spectral curvature above 10 keV.(2016) Koss, M.; Bauer, Franz Erik; Ricci, Claudio; Treister, Ezequiel; Assef T., Roberto; Balokovic, M.; Stern, Daniel.; Gandhi, P.; Lamperti, I.; Alexander, D. M.
- ItemBASS XXXI: Outflow scaling relations in low redshift X-ray AGN host galaxies with MUSE(2022) Kakkad, D.; Sani, E.; Rojas, A. F.; Mallmann, Nicolas D.; Veilleux, S.; Bauer, Franz E.; Ricci, F.; Mushotzky, R.; Koss, M.; Ricci, C.; Treister, E.; Privon, George C.; Nguyen, N.; Bär, R.; Harrison, F.; Oh, K.; Powell, M.; Riffel, R.; Stern, D.; Trakhtenbrot, B.; Urry, C. M.Ionized gas kinematics provide crucial evidence of the impact that active galactic nuclei (AGNs) have in regulating star formation in their host galaxies. Although the presence of outflows in AGN host galaxies has been firmly established, the calculation of outflow properties such as mass outflow rates and kinetic energy remains challenging. We present the [O iii]lambda 5007 ionized gas outflow properties of 22 z<0.1 X-ray AGN, derived from the BAT AGN Spectroscopic Survey using MUSE/VLT. With an average spatial resolution of 1 arcsec (0.1-1.2 kpc), the observations resolve the ionized gas clouds down to sub-kiloparsec scales. Resolved maps show that the [O iii] velocity dispersion is, on average, higher in regions ionized by the AGN, compared to star formation. We calculate the instantaneous outflow rates in individual MUSE spaxels by constructing resolved mass outflow rate maps, incorporating variable outflow density and velocity. We compare the instantaneous values with time-averaged outflow rates by placing mock fibres and slits on the MUSE field-of-view, a method often used in the literature. The instantaneous outflow rates (0.2-275 M-circle dot yr(-1)) tend to be two orders of magnitude higher than the time-averaged outflow rates (0.001-40 M-circle dot yr(-1)). The outflow rates correlate with the AGN bolometric luminosity (L-bol similar to 10(42.71)-10(45.62) erg s(-1)) but we find no correlations with black hole mass (10(6.1)-10(8.9) M-circle dot), Eddington ratio (0.002-1.1), and radio luminosity (10(21)-10(26) W Hz(-1)). We find the median coupling between the kinetic energy and L-bol to be 1 per cent, consistent with the theoretical predictions for an AGN-driven outflow.
- ItemBASS. XXXIII. Swift-BAT Blazars and Their Jets through Cosmic Time(2022) Marcotulli, L.; Ajello, M.; Urry, C. M.; Paliya, V. S.; Koss, M.; Oh, K.; Madejski, G.; Ueda, Y.; Balokovic, M.; Trakhtenbrot, B.; Ricci, F.; Ricci, C.; Stern, D.; Harrison, F.; Powell, M. C.We derive the most up-to-date Swift-Burst Alert Telescope (BAT) blazar luminosity function in the 14-195 keV range, making use of a clean sample of 118 blazars detected in the BAT 105 month survey catalog, with newly obtained redshifts from the BAT Active Galatic Nucleus Spectroscopic Survey. We determine the best-fit X-ray luminosity function for the whole blazar population, as well as for flat-spectrum radio quasars (FSRQs) alone. The main results are: (1) at any redshift, BAT detects the most luminous blazars, above any possible break in their luminosity distribution, which means we cannot differentiate between density and luminosity evolution; (2) the whole blazar population, dominated by FSRQs, evolves positively up to redshift z similar to 4.3, confirming earlier results and implying lower number densities of blazars at higher redshifts than previously estimated. The contribution of this source class to the cosmic X-ray background at 14-195 keV can range from 5%-18%, while possibly accounting for 100% of the MeV background. We also derived the average 14 keV-10 GeV spectral energy distribution for BAT blazars, which allows us to predict the number counts of sources in the MeV range, as well as the expected number of high-energy (>100 TeV) neutrinos. A mission like COSI will detect 40 MeV blazars, of which two may have coincident neutrino detections. Finally, taking into account beaming selection effects, the distribution and properties of the parent population of these extragalactic jets are derived. We find that the distribution of viewing angles is quite narrow, with most sources aligned within <5 degrees of the line of sight. Moreover, the average Lorentz factor, Gamma = 8-12, is lower than previously suggested for these powerful sources.
- ItemBAT AGN Spectroscopic Survey (BASS) – VI. The ΓX–L/LEdd relation.(2017) Trakhtenbrot, Benny; Ricci, Claudio; Treister, Ezequiel; Koss, M.; Schawinski, Kevin; Mushotzky, Richard; Ueda, Yoshihiro; Veilleux, Sylvain; Lamperti, Isabella; Oh, Kyuseok; Stern, Daniel; Harrison, F.; Baloković, Mislav; Gehrels, Neil
- ItemBAT AGN Spectroscopic Survey - III : an observed link between AGN Eddington ratio and narrow-emission-line ratios.(2017) Oh, Kyuseok; Ricci, Claudio; Treister, Ezequiel; Schawinski, Kevin; Koss, M.; Trakhtenbrot, Benny; Lamperti, Isabella; Mushotzky, Richard; Veilleux, Sylvain; Berney, Simon; Crenshaw, D. Michael
- ItemBAT AGN Spectroscopic Survey - IV : near-Infrared Coronal Lines, Hidden Broad Lines, and Correlation with Hard X-ray emission.(2017) Lamperti, Isabella; Ricci, Claudio; Treister, Ezequiel; Koss, M.; Trakhtenbrot, Benny; Schawinski, Kevin; Oh, Kyuseok; Landt, Hermine; Riffel, Rogério; Rodrìguez-Ardila, Alberto; Gehrels, Neil
- ItemBAT AGN Spectroscopic Survey - XII. The relation between coronal properties of active galactic nuclei and the Eddington ratio.(2018) Ricci, Claudio; Bauer, Franz Erik; Treister, Ezequiel; Ho, L. C.; Fabian, AC.; Trakhtenbrot, B.; Koss, M.; Ueda, Y.; Lohfink, A.; Shimizu, T.; Mushotzky, R.
- ItemBAT AGN Spectroscopic Survey XXVII: scattered X-Ray radiation in obscured active galactic nuclei(2021) Gupta, K. K.; Ricci, C.; Tortosa, A.; Ueda, Y.; Kawamuro, T.; Koss, M.; Trakhtenbrot, B.; Oh, K.; Bauer, F. E.; Ricci, F.; Privon, G. C.; Zappacosta, L.; Stern, D.; Kakkad, D.; Piconcelli, E.; Veilleux, S.; Mushotzky, R.; Caglar, T.; Ichikawa, K.; Elagali, A.; Powell, M. C.; Urry, C. M.; Harrison, F.Accreting supermassive black holes (SMBHs), also known as active galactic nuclei (AGN), are generally surrounded by large amounts of gas and dust. This surrounding material reprocesses the primary X-ray emission produced close to the SMBH and gives rise to several components in the broadband X-ray spectra of AGN, including a power-law possibly associated with Thomson-scattered radiation. In this work, we study the properties of this scattered component for a sample of 386 hard-X-ray-selected, nearby (z similar to 0.03) obscured AGN from the 70-month Swift/BAT catalogue. We investigate how the fraction of Thomson-scattered radiation correlates with different physical properties of AGN, such as line-of-sight column density, X-ray luminosity, black hole mass, and Eddington ratio. We find a significant negative correlation between the scattering fraction and the column density. Based on a large number of spectral simulations, we exclude the possibility that this anticorrelation is due to degeneracies between the parameters. The negative correlation also persists when considering different ranges of luminosity, black hole mass, and Eddington ratio. We discuss how this correlation might be either due to the angle dependence of the Thomson cross-section or to more obscured sources having a higher covering factor of the torus. We also find a positive correlation between the scattering fraction and the ratio of [OIII] lambda 5007 to X-ray luminosity. This result is consistent with previous studies and suggests that the Thomson-scattered component is associated with the narrow-line region.
- ItemBAT AGN spectroscopic survey – XV: the high frequency radio cores of ultra-hard X-ray selected AGN(OUP, 2019) Smith, K. L.; Mushotzky, R. F.; Koss, M.; Trakhtenbrot, B.; Ricci, Claudio; Wong, O. I.; Bauer, F. E.; Ricci, F.; Vogel, S.; Stern, D.; Powell, M. C.; Urry, C. M.; Harrison, F.; Mejia-Restrepo, J.; Oh, K.; Baek, J.; Chun, A.We have conducted 22 GHz radio imaging at 1 arcsec resolution of 100 low-redshift AGN selected at 14–195 keV by the Swift-BAT. We find a radio core detection fraction of 96 per cent, much higher than lower frequency radio surveys. Of the 96 radio-detected AGN, 55 have compact morphologies, 30 have morphologies consistent with nuclear star formation, and 11 have sub-kpc to kpc-scale jets. We find that the total radio power does not distinguish between nuclear star formation and jets as the origin of the radio emission. For 87 objects, we use optical spectroscopy to test whether AGN physical parameters are distinct between radio morphological types. We find that X-ray luminosities tend to be higher if the 22 GHz morphology is jet-like, but find no significant difference in other physical parameters. We find that the relationship between the X-ray and core radio luminosities is consistent with the LR/LX ∼ 10−5 of coronally active stars. We further find that the canonical fundamental planes of black hole activity systematically overpredict our radio luminosities, particularly for objects with star formation morphologies.
- ItemBAT AGN spectroscopic survey-II. X-ray emission and high-ionization optical emission lines.(2015) Berney, Simon; Ricci, Claudio; Treister, Ezequiel; Koss, M.; Trakhtenbrot, Benny; Lamperti, Isabella; Schawinski, Kevin; Crenshaw, D. Michael; Fischer, Travis; Gehrels, Neil
- ItemBAT AGN Spectroscopic Survey. I. Spectral Measurements, Derived Quantities, and AGN Demographics.(2017) Koss, M.; Ricci, Claudio; Treister, Ezequiel; Trakhtenbrot, Benny; Lamperti, Isabella; Oh, Kyuseok; Berney, Simon; Schawinski, Kevin; Baloković, Mislav; Baronchelli, Linda; Crenshaw, D. Michael
- ItemBAT AGN Spectroscopic Survey. V. X-Ray Properties of the Swift/BAT 70-month AGN Catalog.(2017) Ricci, Claudio; Treister, Ezequiel; Bauer, Franz Erik; Trakhtenbrot, Benny; Koss, M.; Ueda, Yoshihiro; Del Vecchio, I.; Schawinski, K.; Paltani, S.; Oh, K.; Lamperti, I.
- ItemBROADBAND OBSERVATIONS OF THE COMPTON-THICK NUCLEUS OF NGC 3393(2015) Koss, M.; Romero Cañizales, Cristina; Bauer, Franz Erik
- ItemCompton-thick accretion in the local universe(2015) Ricci, Claudio; Ueda, Y.; Koss, M.; Trakhtenbrot, B.; Bauer, Franz Erik; Gandhi, P.
- ItemDetailed Accretion History of the Supermassive Black Hole in NGC 5972 over the Past ≳104 yr through the Extended Emission-line Region(2022) Finlez, C.; Treister, E.; Bauer, F.; Keel, W.; Koss, M.; Nagar, N.; Sartori, L.; Maksym, W. P.; Venturi, G.; Tubin, D.; Harvey, T.We present integral field spectroscopic observations of NGC 5972 obtained with the Multi-Unit Spectroscopic Explorer at the Very Large Telescope. NGC 5972 is a nearby galaxy containing both an active galactic nucleus (AGN) and an extended emission-line region (EELR) reaching out to similar to 17 kpc from the nucleus. We analyze the physical conditions of the EELR using spatially resolved spectra, focusing on the radial dependence of ionization state together with the light-travel time distance to probe the variability of the AGN on greater than or similar to 10(4) yr timescales. The kinematic analysis suggests multiple components: (a) a faint component following the rotation of the large-scale disk, (b) a component associated with the EELR suggestive of extraplanar gas connected to tidal tails, and (c) a kinematically decoupled nuclear disk. Both the kinematics and the observed tidal tails suggest a major past interaction event. Emission-line diagnostics along the EELR arms typically evidence Seyfert-like emission, implying that the EELR was primarily ionized by the AGN. We generate a set of photoionization models and fit these to different regions along the EELR. This allows us to estimate the bolometric luminosity required at different radii to excite the gas to the observed state. Our results suggest that NGC 5972 is a fading quasar, showing a steady gradual decrease in intrinsic AGN luminosity, and hence the accretion rate onto the SMBH, by a factor similar to 100 over the past 5 x 10(4) yr.
- ItemDetermining the covering factor of compton-thick active galactic nuclei with NuSTAR(2015) Brightman, M.; Balokovic, M.; Stern, D.; Arevalo, P.; Ballantyne, D. R.; Bauer, Franz Erik; Bogg, S. E.; Craig, W. W.; Christensen, F. E.; Comastri, A.; Gandhi, P.; Hailey, C. J.; Harrison, F. A.; Hickox, R. C.; Koss, M.; Lamassa, S.; Fuerst, F.; Puccetti, S.; Rivers, E.; Vasudevan, R.; Walton, D. J.; Zhang, W. W.
- ItemDetermining the radio active galactic nuclei contribution to the radio-far-infrared correlation using the black hole Fundamental Plane relation(2016) Wong, O.; Koss, M.; Schawinski, K.; Kapinska, A.; Lamperti, I.; Oh, K.; Ricci, Claudio; Berney, S.; Trakhtenbrot, B.
- ItemExtended X-ray emission in the IC 2497 - Hanny's Voorwerp system: energy injection in the gas around a fading AGN.(2016) Sartori, Lia F.; Schawinski, Kevin; Koss, M.; Treister, Ezequiel; Maksym, W. Peter; Keel, William C.; Urry, C. Megan; Lintott, Chris J.; Wong, O. Ivy