Michael D. Joner

Michael D. Joner
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Michael D. Joner

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Earth and Planetary Astrophysics (4)
Astrophysics of Galaxies (3)
Solar and Stellar Astrophysics (3)
Cosmology and Nongalactic Astrophysics (2)
Astrophysics (1)
High Energy Astrophysical Phenomena (1)

Publications Authored By Michael D. Joner

We report the discovery of KELT-12b, a highly inflated Jupiter-mass planet transiting a mildly evolved host star. We identified the initial transit signal in the KELT-North survey data and established the planetary nature of the companion through precise follow-up photometry, high-resolution spectroscopy, precise radial velocity measurements, and high-resolution adaptive optics imaging. Our preferred best-fit model indicates that the $V = 10. Read More

Here we present observations of 7 large Kuiper Belt Objects. From these observations, we extract a point source catalog with $\sim0.01"$ precision, and astrometry of our target Kuiper Belt Objects with $0. Read More

The prominent broad Fe II emission blends in the spectra of active galactic nuclei have been shown to vary in response to continuum variations, but past attempts to measure the reverberation lag time of the optical Fe II lines have met with only limited success. Here we report the detection of Fe II reverberation in two Seyfert 1 galaxies, NGC 4593 and Mrk 1511, based on data from a program carried out at Lick Observatory in Spring 2011. Light curves for emission lines including H-beta and Fe II were measured by applying a fitting routine to decompose the spectra into several continuum and emission-line components, and we use cross-correlation techniques to determine the reverberation lags of the emission lines relative to V-band light curves. Read More

We have measured Johnson BV and Cousins RI magnitudes for comparison stars near five TeV blazars. We compare our values with published values, spanning 25 years in some cases, to identify those stars that are most likely proven stable. To avoid zero-point offsets mimicking long-term variability, we based our analysis on the standard deviation between measurements after a mean offset between data sets was removed. Read More

We present dynamical modeling of the broad line region (BLR) in the Seyfert 1 galaxy Mrk 50 using reverberation mapping data taken as part of the Lick AGN Monitoring Project (LAMP) 2011. We model the reverberation mapping data directly, constraining the geometry and kinematics of the BLR, as well as deriving a black hole mass estimate that does not depend on a normalizing factor or virial coefficient. We find that the geometry of the BLR in Mrk 50 is a nearly face-on thick disk, with a mean radius of 9. Read More

This paper reviews results from two projects designed to yield photometry on uniform zero points for five clusters--Coma, the Hyades, M67, NGC 752, and Praesepe. Contributing papers for a project on Cousins VRI photometry and a project on Stromgren-beta photometry are listed. Results of zero point tests of the photometry are reviewed, and their character is found to be satisfactory at the level of a few mmag. Read More

We assess the evolutionary status of the intriguing object Walker 90/V590 Mon, which is located about 20 arcminutes northwest of the Cone Nebula near the center of the open cluster NGC 2264. This object, according to its most recent optical spectral type determination (B7), which we confirmed, is at least 3 magnitudes too faint in V for the cluster distance, but it shows the classical signs of a young pre-main sequence object, such as highly variable Halpha emission, Mg II emission, IR excess, UV continuum, and optical variability. We analyzed a collection of archival and original data on Walker 90, covering 45 years including photometry, imaging, and spectroscopic data ranging from ultraviolet to near-infrared wavelengths. Read More