Search Publications
Magnetic Reconnection at the Earliest Stage of Solar Flux Emergence
Chen, Yajie; Tian, Hui; Zhu, Xiaoshuai +3 more
On 2016 September 20, the Interface Region Imaging Spectrograph observed an active region during its earliest emerging phase for almost 7 hr. The Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory observed continuous emergence of small-scale magnetic bipoles with a rate of ∼1016 Mx s-1. The emergence of …
Eddington-limited Accretion in z ∼ 2 WISE-selected Hot, Dust-obscured Galaxies
Tsai, Chao-Wei; Wright, Edward L.; Jun, Hyunsung D. +12 more
Hot, dust-obscured galaxies, or “Hot DOGs,” are a rare, dusty, hyperluminous galaxy population discovered by the WISE mission. Predominantly at redshifts 2-3, they include the most luminous known galaxies in the universe. Their high luminosities likely come from accretion onto highly obscured supermassive black holes (SMBHs). We have conducted a p…
A Foreground Masking Strategy for [C II] Intensity Mapping Experiments Using Galaxies Selected by Stellar Mass and Redshift
Bock, J.; Zemcov, M.; Cooray, A. R. +11 more
Intensity mapping provides a unique means to probe the epoch of reionization (EoR), when the neutral intergalactic medium was ionized by energetic photons emitted from the first galaxies. The [C II] 158 µm fine-structure line is typically one of the brightest emission lines of star-forming galaxies and thus a promising tracer of the global E…
Binary Pulsar Distances and Velocities from Gaia Data Release 2
Deller, Adam T.; Kaplan, David L.; Chatterjee, Shami +2 more
The second data release from the Gaia mission (Gaia DR2) includes, among its billion entries, astrometric parameters for binary companions to a number of known pulsars, including white dwarf companions to millisecond pulsars (MSPs) and the non-degenerate components of so-called “black widow” and “redback” systems. We find 22 such counterparts in D…
Evidence of a Non-universal Stellar Initial Mass Function. Insights from HST Optical Imaging of Six Ultra-faint Dwarf Milky Way Satellites
Brown, Thomas M.; Gennaro, Mario; Geha, Marla +9 more
Using deep observations obtained with the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope (HST), we demonstrate that the sub-solar stellar initial mass function (IMF) of six ultra-faint dwarf Milky Way satellites (UFDs) is more bottom light than the IMF of the Milky Way disk. Our data have a lower-mass limit of ∼0.45 M ⊙…
The Infrared Emission and Opening Angle of the Torus in Quasars
Ho, Luis C.; Zhuang, Ming-Yang; Shangguan, Jinyi
According to the unified model of active galactic nuclei (AGNs), a putative dusty torus plays an important role in determining an AGN’s external appearance. However, information on the physical properties of the torus is very scarce. We perform detailed decomposition of the infrared (1-500 µm) spectral energy distribution of 76 z < 0.5 Pa…
After the Fall: The Dust and Gas in E+A Post-starburst Galaxies
Draine, B. T.; Dale, D. A.; Crocker, A. F. +11 more
The traditional picture of post-starburst galaxies as dust- and gas-poor merger remnants, rapidly transitioning to quiescence, has been recently challenged. Unexpected detections of a significant interstellar medium (ISM) in many post-starburst galaxies raise important questions. Are they truly quiescent, and if so, what mechanisms inhibit further…
Reconnection Fluxes in Eruptive and Confined Flares and Implications for Superflares on the Sun
Veronig, Astrid M.; Hinterreiter, Jürgen; Pötzi, Werner +2 more
We study the energy release process of a set of 51 flares (32 confined, 19 eruptive) ranging from GOES class B3 to X17. We use Hα filtergrams from Kanzelhöhe Observatory together with Solar Dynamics Observatory HMI and Solar and Heliospheric Observatory MDI magnetograms to derive magnetic reconnection fluxes and rates. The flare reconnection flux …
An Analysis of ALMA Deep Fields and the Perceived Dearth of High-z Galaxies
Finkelstein, Steven L.; Casey, Caitlin M.; Zavala, Jorge A. +5 more
Deep, pencil-beam surveys from ALMA at 1.1-1.3 mm have uncovered an apparent absence of high-redshift dusty galaxies, with existing redshift distributions peaking around z ∼ 1.5-2.5. This has led to a perceived dearth of dusty systems at z ≳ 4 and the conclusion, according to some models, that the early universe was relatively dust-poor. In this p…
Two Episodes of Magnetic Reconnections during a Confined Circular-ribbon Flare
Hou, Yijun; Li, Ting; Yang, Shuhong +2 more
We analyze a unique event with an M1.8 confined circular-ribbon flare on 2016 February 13, with successive formations of two circular ribbons at the same location. The flare had two distinct phases of UV and extreme ultraviolet emissions with an interval of about 270 s, of which the second peak was energetically more important. The first episode w…