Search Publications
An X-Ray + Radio Search for Massive Black Holes in Blue Compact Dwarf Galaxies
Reines, Amy E.; Latimer, Lilikoi J.; Plotkin, Richard M. +2 more
Nearby blue compact dwarf (BCD) galaxies are arguably our best local analogs of galaxies in the earlier universe that may host relics of black hole (BH) seeds. Here we present high-resolution Chandra X-ray Observatory and Karl G. Jansky Very Large Array observations of five nearby BCDs with stellar masses of less than the Small Magellanic Cloud (M…
Evidence for Optically Thick, Eddington-limited Winds Driven by Supercritical Accretion
Feng, Hua; Ho, Luis C.; Yao, Yuhan +1 more
Supercritical accretion onto compact objects powers a massive wind that is optically thick and Eddington-limited. If most of the hard X-rays from the central disk are obscured by the wind, the source will display a blackbody-like spectrum with a luminosity scaled with the mass of the compact object. From the Chandra archive of nearby galaxies, we …
ALMA CO Observations of Supernova Remnant N63A in the Large Magellanic Cloud: Discovery of Dense Molecular Clouds Embedded within Shock-ionized and Photoionized Nebulae
Filipović, M. D.; Rowell, G.; Sasaki, M. +19 more
We carried out new 12CO(J = 1-0, 3-2) observations of a N63A supernova remnant (SNR) from the LMC using the Atacama Large Millimeter/submillimeter Array (ALMA) and Atacama Submillimeter Telescope Experiment. We find three giant molecular clouds toward the northeast, east, and near the center of the SNR. Using the ALMA data, we spatially…
A Search for Spatially Resolved Infrared Rovibrational Molecular Hydrogen Emission from the Disks of Young Stars
Beck, Tracy L.; Bary, Jeffrey S.
We present results from a survey searching for spatially resolved near-infrared line emission from molecular hydrogen gas in the circumstellar environments of nine young stars: AA Tau, AB Aur, DoAr 21, GG Tau, GM Aur, LkCa 15, LkHα 264, UY Aur, and V773 Tau. Prior high-resolution spectra of these stars showed the presence of rovibrational H2<…
Spectral Diagnosis of Mg II and Hα Lines during the Initial Stage of an M6.5 Solar Flare
Xu, Yan; Jing, Ju; Wang, Haimin +2 more
Recent studies have shown special spectral properties during the initial stage of flare emissions, such as the enhanced absorption in He I 10830 Å line and a strong redshift in Hα. Using the high-resolution imaging spectroscopic data obtained by the Interface Region Imaging Spectrograph (IRIS), we investigate the Mg II emission lines during an M6.…
Compton-thick AGN in the NuSTAR Era. IV. A Deep NuSTAR and XMM-Newton View of the Candidate Compton-thick AGN in ESO 116-G018
Ajello, M.; Marchesi, S.; Zhao, X.
We present a 2-78 keV spectral analysis of the deep NuSTAR and XMM-Newton observation of a nearby Seyfert 2 galaxy, ESO 116-G018, which is selected as a candidate Compton-thick (CT) active galactic nucleus (AGN) based on a previous Chandra-Swift-BAT study. Through our analysis, the source is, for the first time, confirmed to be a CT AGN at a >3…
Dwarfs or Giants? Stellar Metallicities and Distances from ugrizG Multiband Photometry
Lewis, Geraint F.; Jensen, Jaclyn; Navarro, Julio F. +19 more
We present a new fully data-driven algorithm that uses photometric data from the Canada-France Imaging Survey (CFIS; u), Pan-STARRS 1 (PS1; griz), and Gaia (G) to discriminate between dwarf and giant stars and to estimate their distances and metallicities. The algorithm is trained and tested using the Sloan Digital Sky Survey (SDSS)/SEGUE spectros…
Reconnection Front Associated with Asymmetric Magnetic Reconnection: Particle-in-cell Simulations
Zhou, Meng; Deng, Xiaohua; Zhong, Zhihong +2 more
Reconnection front (RF) has frequently been observed in the magnetotail and is well known as the dipolarization front in the near-Earth tail. Whether the RF exists in reconnection with distinct plasma/field properties across the reconnecting current sheet (i.e., asymmetric reconnection) is unknown yet. In this Letter, we use 2.5D particle-in-cell …
Tycho's Supernova: The View from Gaia
Bedin, Luigi R.; Ruiz-Lapuente, Pilar; Figueras, Francesca +6 more
SN 1572 (Tycho Brahe’s supernova) clearly belongs to the Ia (thermonuclear) type. It was produced by the explosion of a white dwarf (WD) in a binary system. Its remnant has been the first of this type to be explored in search of a possible surviving companion, the mass donor that brought the WD to the point of explosion. A high peculiar motion wit…
SN 2018hna: 1987A-like Supernova with a Signature of Shock Breakout
Maehara, Hiroyuki; Tominaga, Nozomu; Sasada, Mahito +22 more
High-cadence ultraviolet, optical, and near-infrared photometric and low-resolution spectroscopic observations of the peculiar Type II supernova (SN) 2018hna are presented. The early-phase multiband light curves (LCs) exhibit the adiabatic cooling envelope emission following the shock breakout up to ∼ 14 days from the explosion. SN 2018hna has a r…