Brandon C. Kelly

University Hospitals of Cleveland

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M. Vestergaard

University of Copenhagen

Aneta Siemiginowska

Center for Astrophysics Harvard & Smithsonian

Tommaso Treu

University of California, Los Angeles

C. S. Kochanek

The Ohio State University

K. D. Denney

The Ohio State University

B. M. Peterson

Université Paris Cité

W. N. Brandt

Pennsylvania State University

Anna Pancoast

Center for Astrophysics Harvard & Smithsonian

Ying Zu

Shanghai Jiao Tong University

P. Uttley

University of Amsterdam

Cooperative Institutions

Purple Mountain Observatory

157

Max Planck Society

105

Max Planck Institute for Astronomy

Centre National de la Recherche Scientifique

Center for Astrophysics Harvard & Smithsonian

Goddard Space Flight Center

California Institute of Technology

The Ohio State University

University of Arizona

National Institute for Astrophysics

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Testing the blazar sequence and black hole mass scaling with BL Lac objects

Proceedings of the International Astronomical Union (2010)

Richard M. Plotkin Sera Markoff Scott F. Anderson Brandon C. Kelly Elmar Körding

Abstract Jets from accreting black holes appear remarkably similar over eight orders of magnitude in black hole mass, with more massive black holes generally launching more powerful jets. For example, there is an observed correlation, termed the fundamental plane of black hole accretion, between black hole mass, radio luminosity, and X-ray luminosity. Here, we probe the high-mass tail (10 8 –10 9 M ⊙ ) of the accreting black hole distribution with BL Lac objects. We build SEDs for hundreds of SDSS BL Lacs, and we use these SEDs to test the blazar sequence, a proposed anti-correlation between jet power and peak frequency. We then show our BL Lacs fit on the fundamental plane, supporting the non-linear scaling of jet radiation with black hole mass. The subset of BL Lacs considered here compose the largest sample yet used in the above types of studies, reducing potential selection effects and biases.

Black hole (networking)

10.1017/s1743921310015930

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Citations (41)

The Radio‐Loud Fraction of Quasars is a Strong Function of Redshift and Optical Luminosity

The Astrophysical Journal (2007)

Linhua Jiang Xiaohui Fan Željko Ivezić Gordon T. Richards Donald P. Schneider

Using a sample of optically-selected quasars from the Sloan Digital Sky Survey, we have determined the radio-loud fraction (RLF) of quasars as a function of redshift and optical luminosity. The sample contains more than 30,000 objects and spans a redshift range of 010 to define radio-loud quasars, we find that b_0=-0.132+/-0.116, b_z=-2.052+/-0.261, and b_M=-0.183+/-0.025. The RLF at z=0.5 declines from 24.3% to 5.6% as luminosity decreases from M_{2500}=-26 to M_{2500}=-22, and the RLF at M_{2500}=-26 declines from 24.3% to 4.1% as redshift increases from 0.5 to 3, suggesting that the RLF is a strong function of both redshift and luminosity. We also examine the impact of flux-related selection effects on the RLF determination using a series of tests, and find that the dependence of the RLF on redshift and luminosity is highly likely to be physical, and the selection effects we considered are not responsible for the dependence.

Absolute magnitude

10.1086/510831

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Citations (219)

carma_pack: MCMC sampler for Bayesian inference

ascl (2014)

Brandon C. Kelly Andrew Becker

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Observational Insights Into the Dependence of Quasar Accretion Disk Structure on Black Hole Mass and Accretion Rate

AAS (2007)

Brandon C. Kelly Jill Bechtold Jonathan R. Trump M. Vestergaard Aneta Siemiginowska

Accretion disc

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Measurement Error Models in Astronomy

Brandon C. Kelly

I discuss the effects of measurement error on regression and density estimation. I review the statistical methods that have been developed to correct for measurement error that are most popular in astronomical data analysis, discussing their advantages and disadvantages. I describe functional models for accounting for measurement error in regression, with emphasis on the methods of moments approach and the modified loss function approach. I then describe structural models for accounting for measurement error in regression and density estimation, with emphasis on maximum-likelihood and Bayesian methods. As an example of a Bayesian application, I analyze an astronomical data set subject to large measurement errors and a non-linear dependence between the response and covariate. I conclude with some directions for future research.

Data set

Errors-in-Variables Models

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BoRG: Luminosity Function and Spectroscopic Follow-Up of Galaxies at 8

American Astronomical Society Meeting Abstracts #223 (2014)

K. B. Schmidt Michele Trenti Larry Bradley Brandon C. Kelly Tommaso Treu

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SPACE TELESCOPE AND OPTICAL REVERBERATION MAPPING PROJECT. I. ULTRAVIOLET OBSERVATIONS OF THE SEYFERT 1 GALAXY NGC 5548 WITH THE COSMIC ORIGINS SPECTROGRAPH ONHUBBLE SPACE TELESCOPE

The Astrophysical Journal (2015)

Gisella De Rosa B. M. Peterson Justin Ely G. A. Kriss D. M. Crenshaw

We describe the first results from a six-month long reverberation-mapping experiment in the ultraviolet based on 170 observations of the Seyfert 1 galaxy NGC 5548 with the Cosmic Origins Spectrograph on the Hubble Space Telescope. Significant correlated variability is found in the continuum and broad emission lines, with amplitudes ranging from ~30% to a factor of two in the emission lines and a factor of three in the continuum. The variations of all the strong emission lines lag behind those of the continuum, with He II 1640 lagging behind the continuum by ~2.5 days and Lyman alpha 1215, C IV 1550, and Si IV 1400 lagging by ~5-6 days. The relationship between the continuum and emission lines is complex. In particular, during the second half of the campaign, all emission-line lags increased by a factor of 1.3-2 and differences appear in the detailed structure of the continuum and emission-line light curves. Velocity-resolved cross-correlation analysis shows coherent structure in lag versus line-of-sight velocity for the emission lines; the high-velocity wings of C IV respond to continuum variations more rapidly than the line core, probably indicating higher velocity BLR clouds at smaller distances from the central engine. The velocity-dependent response of Lyman alpha, however, is more complex and will require further analysis.

Reverberation mapping

10.1088/0004-637x/806/1/128

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Citations (138)

CONSTRAINTS ON BLACK HOLE GROWTH, QUASAR LIFETIMES, AND EDDINGTON RATIO DISTRIBUTIONS FROM THE SDSS BROAD-LINE QUASAR BLACK HOLE MASS FUNCTION

The Astrophysical Journal (2010)

Brandon C. Kelly M. Vestergaard Xiaohui Fan Philip F. Hopkins Lars Hernquist

We present an estimate of the black hole mass function of broad-line quasars (BLQSOs) that self-consistently corrects for incompleteness and the statistical uncertainty in the mass estimates, based on a sample of 9886 quasars at 1 < z < 4.5 drawn from the Sloan Digital Sky Survey (SDSS). We find evidence for "cosmic downsizing" of black holes in BLQSOs, where the peak in their number density shifts to higher redshift with increasing black hole mass. The cosmic mass density for black holes seen as BLQSOs peaks at z ∼ 2. We estimate the completeness of the SDSS as a function of the black hole mass and Eddington ratio, and find that at z > 1 it is highly incomplete at MBH ≲ 109 M☉ and L/LEdd ≲ 0.5. We estimate a lower limit on the lifetime of a single BLQSO phase to be tBL > 150 ± 15 Myr for black holes at z = 1 with a mass of MBH = 109 M☉, and we constrain the maximum mass of a black hole in a BLQSO to be ∼3 × 1010 M☉. Our estimated distribution of BLQSO Eddington ratios peaks at L/LEdd ∼ 0.05 and has a dispersion of ∼0.4 dex, implying that most BLQSOs are not radiating at or near the Eddington limit; however, the location of the peak is subject to considerable uncertainty. The steep increase in number density of BLQSOs toward lower Eddington ratios is expected if the BLQSO accretion rate monotonically decays with time. Furthermore, our estimated lifetime and Eddington ratio distributions imply that the majority of the most massive black holes spend a significant amount of time growing in an earlier obscured phase, a conclusion which is independent of the unknown obscured fraction. These results are consistent with models for self-regulated black hole growth, at least for massive systems at z > 1, where the BLQSO phase occurs at the end of a fueling event when black hole feedback unbinds the accreting gas, halting the accretion flow.

Black hole (networking)

Line (geometry)

10.1088/0004-637x/719/2/1315

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Citations (160)

クェーサーにおけるRADIO LOUDNESS分布二分法を開示する: SDSS-FIRSTクェーサーサンプルに適用された不偏モンテカルロ法

The Astrophysical Journal (2012)

M. Baloković V. Smolčić Željko Ivezić G. Zamorani E. Schinnerer

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VizieR Online Data Catalog: Space telescope RM project. VIII. NGC5548 HST sp. (Kriss+, 2019)