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Articles 1 - 13 of 13
Full-Text Articles in Physical Sciences and Mathematics
A Normal Supermassive Black Hole In Ngc 1277, Alister W. Graham, Mark Durré, Giulia A.D. Savorgnan, Anne M. Medling, Dan Batcheldor, Nicholas Scott, Beverly Watson, Alessandro Marconi
A Normal Supermassive Black Hole In Ngc 1277, Alister W. Graham, Mark Durré, Giulia A.D. Savorgnan, Anne M. Medling, Dan Batcheldor, Nicholas Scott, Beverly Watson, Alessandro Marconi
Aerospace, Physics, and Space Science Faculty Publications
The identification of galaxies with “overly massive” black holes requires two measurements: a black hole mass (Mbh) and a host spheroid mass (Msph,*). Here we provide our measurements for NGC 1277. Our structural decomposition reveals that NGC 1277 is dominated by a “classical” spheroid with a Sérsic index n = 5.3, a half-light radius Rₑmajor: You have a new taskSpace: You have a new task,major = 2.1 kpc, and a stellar mass of 2.7 10^11 11 M⊙ (using M*/ LV = 11.65, Martín-Navarro et al.). This mass is an order of magnitude greater than originally reported. Using the latest Mbh–n, …
Chang-Es V: Nuclear Outflow In A Virgo Cluster Spiral After A Tidal Disruption Event, Judith A. Irwin, Richard N. Henriksen, Marita Krause, Daniel Q. Wang, Theresa Wiegert, Eric J. Murphy, George Heald, Eric S. Perlman
Chang-Es V: Nuclear Outflow In A Virgo Cluster Spiral After A Tidal Disruption Event, Judith A. Irwin, Richard N. Henriksen, Marita Krause, Daniel Q. Wang, Theresa Wiegert, Eric J. Murphy, George Heald, Eric S. Perlman
Aerospace, Physics, and Space Science Faculty Publications
We have observed the Virgo Cluster spiral galaxy, NGC 4845, at 1.6 and 6 GHz using the Karl G. Jansky Very Large Array, as part of the Continuum Halos in Nearby Galaxies—an EVLA Survey (CHANG-ES). The source consists of a bright unresolved core with a surrounding weak central disk (1.8 kpc diameter). The core is variable over the 6 month timescale of the CHANG-ES data and has increased by a factor of ≈6 since 1995. The wide bandwidths of CHANG-ES have allowed us to determine the spectral evolution of this core, which peaks between 1.6 and 6 GHz (it is …
The Differences In The Torus Geometry Between Hidden And Non-Hidden Broad Line Active Galactic Nuclei, Kohei Ichikawa, Eric S. Perlman
The Differences In The Torus Geometry Between Hidden And Non-Hidden Broad Line Active Galactic Nuclei, Kohei Ichikawa, Eric S. Perlman
Aerospace, Physics, and Space Science Faculty Publications
We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGNs) with clumpy torus models. We compiled high spatial resolution (∼0.3–0.7 arcsec) mid-IR (MIR) N-band spectroscopy, Q-band imaging, and nuclear near- and MIR photometry from the literature. Combining these nuclear near- and MIR observations, far-IR photometry, and clumpy torus models enables us to put constraints on the torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties: type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published …
Spitzer Space Telescope Measurements Of Dust Reverberation Lags In The Seyfert 1 Galaxy Ngc 6418, Billy Vazquez, Dan Batcheldor
Spitzer Space Telescope Measurements Of Dust Reverberation Lags In The Seyfert 1 Galaxy Ngc 6418, Billy Vazquez, Dan Batcheldor
Aerospace, Physics, and Space Science Faculty Publications
We present results from a 15 month campaign of high-cadence (∼3 days) mid-infrared Spitzer and optical (B and V) monitoring of the Seyfert 1 galaxy NGC 6418, with the objective of determining the characteristic size of the dusty torus in this active galactic nucleus (AGN). We find that the 3.6 and 4.5 μm flux variations lag behind those of the optical continuum by 37.2 ^+2.4 _-2.2 days and -47.1 ^+3.1 _-3.1 days, respectively. We report a cross-correlation time lag between the 4.5 and 3.6 μm flux of 13.9 ^+0.5 _-0.1 days. The lags indicate that the dust emitting at 3.6 …
Recoiling Supermassive Black Holes: A Search In The Nearby Universe, Davide Lena, Andrew Edward Robinson, Alessandro Marconi, David J. Axon, Alessandro Capetti, David Merritt, Daniel P. Batcheldor
Recoiling Supermassive Black Holes: A Search In The Nearby Universe, Davide Lena, Andrew Edward Robinson, Alessandro Marconi, David J. Axon, Alessandro Capetti, David Merritt, Daniel P. Batcheldor
Aerospace, Physics, and Space Science Faculty Publications
The coalescence of a binary black hole can be accompanied by a large gravitational recoil due to anisotropic emission of gravitational waves. A recoiling supermassive black hole (SBH) can subsequently undergo long-lived oscillations in the potential well of its host galaxy, suggesting that offset SBHs may be common in the cores of massive ellipticals. We have analyzed Hubble Space Telescope archival images of 14 nearby core ellipticals, finding evidence for small (≲ 10 pc) displacements between the active galactic nucleus (AGN; the location of the SBH) and the center of the galaxy (the mean photocenter) in 10 of them. Excluding …
Uncovering The Deeply Embedded Active Galactic Nucleus Activity In The Nuclear Regions Of The Interacting Galaxy Arp 299, A Alonso-Herrero, Eric S. Perlman
Uncovering The Deeply Embedded Active Galactic Nucleus Activity In The Nuclear Regions Of The Interacting Galaxy Arp 299, A Alonso-Herrero, Eric S. Perlman
Aerospace, Physics, and Space Science Faculty Publications
We present mid-infrared (MIR) 8-13 μm spectroscopy of the nuclear regions of the interacting galaxy Arp 299 (IC 694+NGC 3690) obtained with CanariCam (CC) on the 10.4 m Gran Telescopio Canarias (GTC). The high angular resolution (∼0.″3-0.″6) of the data allows us to probe nuclear physical scales between 60 and 120 pc, which is a factor of 10 improvement over previous MIR spectroscopic observations of this system. The GTC/CC spectroscopy displays evidence of deeply embedded active galactic nucleus (AGN) activity in both nuclei. The GTC/CC nuclear spectrum of NGC 3690/Arp 299-B1 can be explained as emission from AGN-heated dust in …
X-Ray Nuclear Activity In S4g Barred Galaxies: No Link Between Bar Strength And Co-Occurrent Supermassive Black Hole Fueling, Mauricio Cristernas, Trisha Mizusawa
X-Ray Nuclear Activity In S4g Barred Galaxies: No Link Between Bar Strength And Co-Occurrent Supermassive Black Hole Fueling, Mauricio Cristernas, Trisha Mizusawa
Aerospace, Physics, and Space Science Faculty Publications
Stellar bars can lead to gas inflow toward the center of a galaxy and stimulate nuclear star formation. However, there is no compelling evidence on whether they also feed a central supermassive black hole: by measuring the fractions of barred active and inactive galaxies, previous studies have yielded conflicting results. In this paper, we aim to understand the lack of observational evidence for bar-driven active galactic nucleus (AGN) activity by studying a sample of 41 nearby (d < 35 Mpc) barred galaxies from the Spitzer Survey for Stellar Structure in Galaxies. We use Chandra observations to measure nuclear 2–10 keV X-ray luminosities and estimate Eddington ratios, together with Spitzer 3.6 μm imaging to quantify the strength of the stellar bar in two independent ways: (1) from its structure, as traced by its ellipticity and boxiness, and (2) from its gravitational torque Qb, taken as the maximum ratio of the tangential force to the mean background radial force. In this way, rather than discretizing the presence of both stellar bars and nuclear activity, we are able to account for the continuum of bar strengths and degrees of AGN activity. We find nuclear X-ray sources in 31 out of 41 galaxies with median X-ray luminosity and Eddington ratio of LX = 4.3×1038 erg s−1 and Lbol/LEdd = 6.9×10−6, respectively, consistent with low-luminosity AGN activity. Including upper limits for those galaxies without nuclear detections, we find no significant correlation between any of the bar strength indicators and the degree of nuclear activity, irrespective of galaxy luminosity, stellar mass, Hubble type, or bulge size. Strong bars do not favor brighter or more efficient nuclear activity, implying that at least for the low-luminosity regime, supermassive black hole fueling is not closely connected to large-scale features.
The 2010 Very High Energy Y-Ray Flare And 10 Years Of Multi-Wavelength Observations Of M 87, A. Abramowski, Mihai Cara, Eric S. Perlman, The H.E.S.S. Collaboration, The Magic Collaboration
The 2010 Very High Energy Y-Ray Flare And 10 Years Of Multi-Wavelength Observations Of M 87, A. Abramowski, Mihai Cara, Eric S. Perlman, The H.E.S.S. Collaboration, The Magic Collaboration
Aerospace, Physics, and Space Science Faculty Publications
The giant radio galaxy M 87 with its proximity (16 Mpc), famous jet, and very massive black hole ((3 – 6) × 109 M ☉) provides a unique opportunity to investigate the origin of very high energy (VHE; E > 100 GeV) γ-ray emission generated in relativistic outflows and the surroundings of supermassive black holes. M 87 has been established as a VHE γ-ray emitter since 2006. The VHE γ-ray emission displays strong variability on timescales as short as a day. In this paper, results from a joint VHE monitoring campaign on M 87 by the MAGIC and VERITAS instruments in …
Optical Polarization And Spectral Variability In The M87 Jet, Eric S. Perlman, Mihai Cara, Matthew Bourque, Raymond C. Simons
Optical Polarization And Spectral Variability In The M87 Jet, Eric S. Perlman, Mihai Cara, Matthew Bourque, Raymond C. Simons
Aerospace, Physics, and Space Science Faculty Publications
During the last decade, M87's jet has been the site of an extraordinary variability event, with one knot (HST-1) increasing by over a factor 100 in brightness. Variability has also been seen on timescales of months in the nuclear flux. Here we discuss the optical-UV polarization and spectral variability of these components, which show vastly different behavior. HST-1 shows a highly significant correlation between flux and polarization, with P increasing from 20% at minimum to >40% at maximum, while the orientation of its electric vector stayed constant. HST-1's optical-UV spectrum is very hard (αUV-O 0.5, F ν ∞ ν-α), and …
Nicmos Polarimetry Of "Polar-Scattered" Seyfert 1 Galaxies, Daniel P. Batcheldor, Andrew Edward Robinson, David J. Axon, Stuart Young, S Quinn, James E. Smith, James H. Hough, David M. Alexander
Nicmos Polarimetry Of "Polar-Scattered" Seyfert 1 Galaxies, Daniel P. Batcheldor, Andrew Edward Robinson, David J. Axon, Stuart Young, S Quinn, James E. Smith, James H. Hough, David M. Alexander
Aerospace, Physics, and Space Science Faculty Publications
The nuclei of Seyfert 1 galaxies exhibit a range of optical polarization characteristics that can be understood in terms of two scattering regions producing orthogonal polarizations: an extended polar scattering region (PSR) and a compact equatorial scattering region (ESR), located within the circum-nuclear torus. Here we present NICMOS 2.0 μm imaging polarimetry of six "polar-scattered" Seyfert 1 (S1) galaxies, in which the PSR dominates the optical polarization. The unresolved nucleus (<058) is significantly polarized in only three objects, but five of the six exhibit polarization in a 058-15 circum-nuclear annulus. In Fairall 51 and ESO 323-G077, the polarization position angle at 2 μm (θ2 μm) is consistent with the average for the optical spectrum(θv), implying that the nuclear polarization is dominated by polar scattering at both wavelengths. The same is probably true for NGC3227. In both NGC 4593 and Mrk 766, there is a large difference between θ2 μm and θv off-nucleus, where polar scattering is expected to dominate. This may be due to contamination by interstellar polarization in NGC4593, but there is no clear explanation in the case of the strongly polarized Mrk766. Lastly, in Mrk1239, a large change (60°) in θ2 μm between the nucleus and the annulus indicates that the unresolved nucleus and its immediate surroundings have different polarization states at 2μm, which we attribute to the ESR and PSR, respectively. A further implication is that the source of the scattered 2 μm emission in the unresolved nucleus is the accretion disk, rather than torus hot dust emission.
Broad Lyα Emission From Three Nearby Bl Lacertae Objects, John T. Stocke, Charles W. Danforth, Eric S. Perlman
Broad Lyα Emission From Three Nearby Bl Lacertae Objects, John T. Stocke, Charles W. Danforth, Eric S. Perlman
Aerospace, Physics, and Space Science Faculty Publications
We present far-UV HST/COS spectra of four nearby BLLac objects. BLLac spectra are dominated by a smooth, power-law continuum which arises in a relativistic jet. However, the spectra are not necessarily featureless; weak, broad- and/or narrow-line emission is sometimes seen in high-quality optical spectra. We present detections of Lyα emission in HST/COS spectra of Mrk421 (z = 0.030) and PKS2005-489 (z = 0.071) as well as an archival HST/GHRS observation of Mrk501 (z = 0.0337). Archival HST/STIS observations of PKS2155-304 (z = 0.116) show no Lyα emission to a very low upper limit. Using the assumption that the broad-line region …
A Displaced Supermassive Black Hole In M87, Daniel P. Batcheldor, A. Robinson, D. J. Axon, Eric S. Perlman, D. Merritt
A Displaced Supermassive Black Hole In M87, Daniel P. Batcheldor, A. Robinson, D. J. Axon, Eric S. Perlman, D. Merritt
Aerospace, Physics, and Space Science Faculty Publications
Isophotal analysis of M87, using data from the Advanced Camera for Surveys, reveals a projected displacement of 6.8 ± 0.8 pc (~0farcs1) between the nuclear point source (presumed to be the location of the supermassive black hole, SMBH) and the photo-center of the galaxy. The displacement is along a position angle of 307° ± 17° and is consistent with the jet axis. This suggests the active SMBH in M87 does not currently reside at the galaxy center of mass, but is displaced in the counter-jet direction. Possible explanations for the displacement include orbital motion of an SMBH binary, gravitational perturbations …
Gemini Mid-Ir Polarimetry Of Ngc 1068: Polarized Structures Around The Nucleus, Christopher C. Packham, Stuart Young, Scott E. Fisher, Kevin M. Volk, Rachel E. Mason, James H. Hough, Patrick F. Roche, Moshe Elitzur, James T. Radomski, Eric S. Perlman
Gemini Mid-Ir Polarimetry Of Ngc 1068: Polarized Structures Around The Nucleus, Christopher C. Packham, Stuart Young, Scott E. Fisher, Kevin M. Volk, Rachel E. Mason, James H. Hough, Patrick F. Roche, Moshe Elitzur, James T. Radomski, Eric S. Perlman
Aerospace, Physics, and Space Science Faculty Publications
We present diffraction-limited, 10 μm imaging polarimetry data for the central regions of the archetypal Seyfert active galactic nucleus NGC 1068. The position angle of polarization is consistent with three dominant polarizing mechanisms. We identify three distinct regions of polarization: (1) north of the nucleus, arising from aligned dust in the narrow emission line region, (2) south, east, and west of the nucleus, consistent with dust being channeled toward the central engine, and (3) a central minimum of polarization consistent with a compact (≤22 pc) torus. These observations provide continuity between the geometrically and optically thick torus and the host …