Shawn Poindexter

REVERBERATION MAPPING MEASUREMENTS OF BLACK HOLE MASSES IN SIX LOCAL SEYFERT GALAXIES

We present the final results from a high sampling rate, multi-month, spectrophotometric reverberation mapping campaign undertaken to obtain either new or improved Hβ reverberation lag measurements for several relatively low-luminosity active galactic nuclei (AGNs). We have reliably measured the time delay between variations in the continuum and Hβ emission line in six local Seyfert 1 galaxies. These measurements are used to calculate the mass of the supermassive black hole at the center of each of these AGNs. We place our results in context to the most current calibration of the broad-line region (BLR) RBLR–L relationship, where our results remove outliers and reduce the scatter at the low-luminosity end of this relationship. We also present velocity-resolved Hβ time-delay measurements for our complete sample, though the clearest velocity-resolved kinematic signatures have already been published.

Microlens OGLE-2005-BLG-169 Implies That Cool Neptune-like Planets Are Common

We detect a Neptune mass ratio (q 8 ? 10-5) planetary companion to the lens star in the extremely high magnification (A ~ 800) microlensing event OGLE-2005-BLG-169. If the parent is a main-sequence star, it has mass M ~ 0.5 M?, implying a planet mass of ~13 M? and projected separation of ~2.7 AU. When intensely monitored over their peak, high-magnification events similar to OGLE-2005-BLG-169 have nearly complete sensitivity to Neptune mass ratio planets with projected separations of 0.6-1.6 Einstein radii, corresponding to 1.6-4.3 AU in the present case. Only two other such events were monitored well enough to detect Neptunes, and so this detection by itself suggests that Neptune mass ratio planets are common. Moreover, another Neptune was recently discovered at a similar distance from its parent star in a low-magnification event, which are more common but are individually much less sensitive to planets. Combining the two detections yields 90% upper and lower frequency limits f = 0.38 over just 0.4 decades of planet-star separation. In particular, f > 16% at 90% confidence. The parent star hosts no Jupiter-mass companions with projected separations within a factor 5 of that of the detected planet. The lens-source relative proper motion is ? ~ 7-10 mas yr-1, implying that if the lens is sufficiently bright, I 23.8, it will be detectable by the Hubble Space Telescope by 3 years after peak. This would permit a more precise estimate of the lens mass and distance and, so, the mass and projected separation of the planet. Analogs of OGLE-2005-BLG-169Lb orbiting nearby stars would be difficult to detect by other methods of planet detection, including radial velocities, transits, and astrometry.

The Kilodegree Extremely Little Telescope (KELT): A Small Robotic Telescope for Large‐Area Synoptic Surveys

ABSTRACT The Kilodegree Extremely Little Telescope (KELT) project is a survey for planetary transits of bright stars. It consists of a small‐aperture, wide‐field automated telescope located at Winer Observatory near Sonoita, Arizona. The telescope surveys a set of 26° × 26° fields that together cover about 25% of the northern sky, and targets stars in the range of \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

The Spatial Structure of an Accretion Disk

8< V< 10

X-RAY MICROLENSING IN RXJ1131-1231 AND HE1104-1805

\end{document} mag, searching for transits by close‐in Jupiters. This paper describes the system hardware and...

A REVISED BROAD-LINE REGION RADIUS AND BLACK HOLE MASS FOR THE NARROW-LINE SEYFERT 1 NGC 4051

Based on the microlensing variability of the two-image gravitational lens HE 1104-1805 observed between 0.4 and 8 μm, we have measured the size and wavelength-dependent structure of the quasar accretion disk. Modeled as a power law in temperature, T ∝ R−β, we measure a B-band (0.13 μm in the rest frame) half-light radius of R1/2,B = 6.7+ 6.2−3.2 × 1015 cm (68% confidence level) and a logarithmic slope of β = 0.61+ 0.21−0.17 (68% confidence level) for our standard model with a logarithmic prior on the disk size. Both the scale and the slope are consistent with simple thin disk models where β = 3/4 and R1/2,B = 5.9 × 1015 cm for a Shakura-Sunyaev disk radiating at the Eddington limit with 10% efficiency. The observed fluxes favor a slightly shallower slope, β = 0.55+ 0.03−0.02, and a significantly smaller size for β = 3/4.

DIVERSE KINEMATIC SIGNATURES FROM REVERBERATION MAPPING OF THE BROAD-LINE REGION IN AGNs

We present results from a monitoring campaign performed with the Chandra X-ray Observatory of the gravitationally lensed quasars RX J1131–1231 and HE 1104–1805. We detect significant X-ray variability in all images of both quasars. The flux variability detected in image A of RX J1131–1231 is of particular interest because of its high amplitude (a factor of ~ 20). We interpret it as arising from microlensing since the variability is uncorrelated with that of the other images and the X-ray flux ratios show larger changes than the optical as we would expect for microlensing of the more compact X-ray emission regions. The differences between the X-ray and optical flux ratios of HE 1104–1805 are less dramatic, but there is no significant soft X-ray or dust absorption, implying the presence of X-ray microlensing in this system as well. Combining the X-ray data with the optical light curves we find that the X-ray emitting region of HE 1104–1805 is compact with a half-light radius 6rg , where the gravitational radius is r g = 3.6 × 1014 cm, thus placing significant constraints on AGN corona models. We also find that the microlensing in HE 1104–1805 favors mass models for the lens galaxy that are dominated by dark matter. Finally, we better characterize the massive foreground cluster near RX J1131–1231, set limits on other sources of extended X-ray emission, and limit the fluxes of any central odd images to be 30-50 (3σ) times fainter than the observed images.

MICROLENSING EVIDENCE THAT A TYPE 1 QUASAR IS VIEWED FACE-ON

We present the first results from a high sampling rate, multimonth reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from telescopes around the world. The primary goal of this campaign was to obtain either new or improved Hβ reverberation lag measurements for several relatively low luminosity active galactic nuclei (AGNs). We feature results for NGC 4051 here because, until now, this object has been a significant outlier from AGN scaling relationships, e.g., it was previously a ∼2–3σ outlier on the relationship between the broad-line region (BLR) radius and the optical continuum luminosity—the RBLR–L relationship. Our new measurements of the lag time between variations in the continuum and Hβ emission line made from spectroscopic monitoring of NGC 4051 lead to a measured BLR radius of RBLR = 1.87 +0.54 −0.50 light days and black hole mass of MBH = (1.73 +0.55 −0.52 ) × 10 6 M� . This radius is consistent with that expected from the RBLR–L relationship, based on the present luminosity of NGC 4051 and the most current calibration of the relation by Bentz et al.. We also present a preliminary look at velocity-resolved Hβ light curves and time delay measurements, although we are unable to reconstruct an unambiguous velocity-resolved reverberation signal.

MID-IR OBSERVATIONS AND A REVISED TIME DELAY FOR THE GRAVITATIONAL LENS SYSTEM QUASAR HE 1104 1805

A detailed analysis of the data from a high sampling rate, multi-month reverberation mapping campaign, undertaken primarily at MDM Observatory with supporting observations from telescopes around the world, reveals that the Hbeta emission region within the broad line regions (BLRs) of several nearby AGNs exhibit a variety of kinematic behaviors. While the primary goal of this campaign was to obtain either new or improved Hbeta reverberation lag measurements for several relatively low luminosity AGNs (presented in a separate work), we were also able to unambiguously reconstruct velocity-resolved reverberation signals from a subset of our targets. Through high cadence spectroscopic monitoring of the optical continuum and broad Hbeta emission line variations observed in the nuclear regions of NGC 3227, NGC 3516, and NGC 5548, we clearly see evidence for outflowing, infalling, and virialized BLR gas motions, respectively.

The Transverse Peculiar Velocity of the Q2237+0305 Lens Galaxy and the Mean Mass of its Stars

Using a microlensing analysis of 11 years of OGLE V-band photometry of the four image gravitational lens Q2237+0305, we measure the inclination i of the accretion disk to be cos i> 0.66 at 68% confidence. Very edge on (cos i< 0.39) solutions are ruled out at 95% confidence. We measure theV-band radius of the accretion disk, defined by the radius where the temperature matches the monitoring band photon emission, to be RV = 5.8 +3.8 −2.3 × 10 15 cm assuming a simple thin disk model and including the uncertainties in its inclination. The projected radiating area of the disk remains too large to be consistent with the observed flux for a T ∝ R −3/4 thin disk temperature profile. There is no strong correlation between the direction of motion (peculiar velocity) of the lens galaxy and the orientation of the disk.