Search Publications
A New Candidate Transitional Millisecond Pulsar in the Subluminous Disk State: 4FGL J0407.7-5702
Strader, Jay; Dage, Kristen C.; Chomiuk, Laura +7 more
We report the discovery of a variable optical and X-ray source within the error ellipse of the previously unassociated Fermi Large Area Telescope γ-ray source 4FGL J0407.7-5702. A 22 ks observation from XMM-Newton/European Photon Imaging Camera (EPIC) shows an X-ray light curve with rapid variability and flaring. The X-ray spectrum is well fit by …
The Proper Motion of the Central Compact Object RX J0822-4300 in the Supernova Remnant Puppis A, Revisited
Kraft, Ralph; Becker, Werner; Winkler, P. Frank +2 more
We present an improved proper-motion measurement of the central compact object RX J0822-4300, located in the supernova remnant Puppis A. By employing a new data set taken in 2019 February by the High Resolution Camera on board the Chandra X-ray Observatory, we approximately double the available temporal baseline for our analysis to slightly more t…
Final Spitzer IRAC Observations of the Rise and Fall of SN 1987A
Gehrz, Robert D.; Woodward, Charles E.; Arendt, Richard G. +4 more
Spitzer's final Infrared Array Camera observations of SN 1987A show the 3.6 and 4.5 µm emission from the equatorial ring (ER) continues a period of steady decline. Deconvolution of the images reveals that the emission is dominated by the ring, not the ejecta, and is brightest on the west side. Decomposition of the marginally resolved emissio…
Free-form Lens Model and Mass Estimation of the High-redshift Galaxy Cluster ACT-CL J0102-4915, "El Gordo"
Sharon, K.; Zitrin, A.; Coe, D. +7 more
We examine the massive colliding cluster El Gordo, one of the most massive clusters at high redshift. We use a free-form lensing reconstruction method that avoids making assumptions about the mass distribution. We use data from the RELICS program and identify new multiply lensed system candidates. The new set of constraints and free-form method pr…
Deciphering the 3D Orion Nebula-I: Expanding Shells in the Huygens Region
Abel, N. P.; O'Dell, C. R.; Ferland, G. J.
Based on imaging and spectroscopic data, we develop a 3D model for the Huygens Region of the Orion Nebula. θ^{1} Ori C, the hottest star in the Trapezium, is surrounded by a wind-blown Central Bubble that opens SW into the Extended Orion Nebula. Outside of this feature lies a layer of ionized gas at about 0.4 pc from θ^{1} Ori C. Both of these fea…
Probing Interstellar Grain Growth through Polarimetry in the Taurus Cloud Complex
Hoang, Thiem; Andersson, B. -G.; Vaillancourt, John E. +4 more
The optical and near-infrared (OIR) polarization of starlight is typically understood to arise from the dichroic extinction of that light by dust grains whose axes are aligned with respect to a local magnetic field. The size distribution of the aligned-grain population can be constrained by measurements of the wavelength dependence of the polariza…
The Late-time Afterglow Evolution of Long Gamma-Ray Bursts GRB 160625B and GRB 160509A
Fruchter, Andrew S.; Cenko, S. Bradley; Tanvir, Nial +12 more
We present post-jet-break Hubble Space Telescope, Very Large Array, and Chandra observations of the afterglow of the long γ-ray bursts GRB 160625B (between 69 and 209 days) and GRB 160509A (between 35 and 80 days). We calculate the post-jet-break decline rates of the light curves and find the afterglow of GRB 160625B is inconsistent with a simple …
High-resolution Spectroscopic Monitoring Observations of FU Orionis-type Object, V960 Mon
Lee, Jeong-Eun; Pyo, Tae-Soo; Park, Sunkyung +9 more
We present the results of high-resolution (R ≥ 30,000) optical and near-infrared (NIR) spectroscopic monitoring observations of an FU Orionis-type object (FUor), V960 Mon, which underwent an outburst in 2014 November. We have monitored this object with the Bohyunsan Optical Echelle Spectrograph and the Immersion GRating INfrared Spectrograph since…
Blazar Variability: A Study of Nonstationarity and the Flux-Rms Relation
Bhattacharyya, Joy; Ghosh, Ritesh; Chatterjee, Ritaban +1 more
We analyze X-ray light curves of the blazars Mrk 421, PKS 2155-304, and 3C 273 using observations by the Soft X-ray Telescope on board AstroSat and archival XMM-Newton data. We use light curves of length 30-90 ks from three to four epochs for all three blazars. We apply the autoregressive integrated moving average model, which indicates the variab…
TESS Asteroseismic Analysis of the Known Exoplanet Host Star HD 222076
Chaplin, William J.; Kane, Stephen R.; Stassun, Keivan G. +22 more
The Transiting Exoplanet Survey Satellite (TESS) is an all-sky survey mission aiming to search for exoplanets that transit bright stars. The high-quality photometric data of TESS are excellent for the asteroseismic study of solar-like stars. In this work, we present an asteroseismic analysis of the red-giant star HD 222076 hosting a long-period (2…