Search Publications
ΣSFR-M∗ Diagram: A Valuable Galaxy Evolution Diagnostic to Complement (s)SFR-M∗ Diagrams
Ellison, Sara L.; Faber, S. M.; Tacchella, Sandro +3 more
The specific star formation rate (sSFR) is commonly used to describe the level of galaxy star formation (SF) and to select quenched galaxies. However, since it is a relative measure of the young-to-old population, an ambiguity in its interpretation may arise because a low sSFR can be due to either a substantial previous mass buildup or SF activity…
Evidence for Low-power Radio Jet-ISM Interaction at 10 pc in the Dwarf AGN Host NGC 4395
Stalin, C. S.; Riffel, Rogemar A.; Nandi, Payel +10 more
Black-hole-driven outflows in galaxies hosting active galactic nuclei (AGN) may interact with their interstellar medium (ISM) affecting star formation (SF). Such feedback processes, reminiscent of those seen in massive galaxies, have been reported recently in some dwarf galaxies. However, such studies have usually been on kiloparsec and larger sca…
Investigating the Magnetic Structure of Interplanetary Coronal Mass Ejections Using Simultaneous Multispacecraft In Situ Measurements
Farrugia, C. J.; Galvin, A. B.; Davies, E. E. +5 more
In situ measurements from spacecraft typically provide a time series at a single location through coronal mass ejections (CMEs), and they have been one of the main methods to investigate CMEs. The CME properties derived from these in situ measurements are affected by temporal changes that occur as the CME passes over the spacecraft, such as radial…
Dependence of Chemical Abundance on the Cosmic-Ray Ionization Rate in IC 348
Li, Di; Wang, Junzhi; Yue, Nannan +8 more
Ions (e.g., ${{\rm{H}}}_{3}^{+}$ , H2O+) have been used extensively to quantify the cosmic-ray ionization rate (CRIR) in diffuse sightlines. However, measurements of the CRIR in low-to-intermediate density gas environments are rare, especially when background stars are absent. In this work, we combine molecular line observati…
The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER). V. The Structure of M33 in Resolved Stellar Populations
Bell, Eric F.; Williams, Benjamin F.; Choi, Yumi +14 more
We present a detailed analysis of the structure of the Local Group flocculent spiral galaxy M33, as measured using the Panchromatic Hubble Andromeda Treasury Triangulum Extended Region (PHATTER) survey. Leveraging the multiwavelength coverage of PHATTER, we find that the oldest populations are dominated by a smooth exponential disk with two distin…
CHIME Discovery of a Binary Pulsar with a Massive Nondegenerate Companion
Ransom, Scott M.; van Kerkwijk, M. H.; Kaspi, Victoria M. +25 more
Of the more than 3000 radio pulsars currently known, only ~300 are in binary systems, and only five of these consist of young pulsars with massive nondegenerate companions. We present the discovery and initial timing, accomplished using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope, of the sixth such binary pulsar, PSR J2108…
AGN STORM 2. II. Ultraviolet Observations of Mrk 817 with the Cosmic Origins Spectrograph on the Hubble Space Telescope
Gorjian, Varoujan; Treu, Tommaso; Kaspi, Shai +62 more
We present reverberation mapping measurements for the prominent ultraviolet broad emission lines of the active galactic nucleus Mrk 817 using 165 spectra obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope. Our ultraviolet observations are accompanied by X-ray, optical, and near-infrared observations as part of the AGN Spac…
Catalog of Magnetic White Dwarfs with Hydrogen Dominated Atmospheres
Kepler, S. O.; Jordan, S.; Romero, A. D. +2 more
White dwarfs are excellent research laboratories as they reach temperatures, pressures, and magnetic fields that are unattainable on Earth. To better understand how these three physical parameters interact with each other and with other stellar features, we determined the magnetic field strength for a total of 804 hydrogen-rich white dwarfs (WDs) …
Finding r-II Sibling Stars in the Milky Way with the Greedy Optimistic Clustering Algorithm
Hattori, Kohei; Roederer, Ian U.; Okuno, Akifumi
R-process enhanced stars with [Eu/Fe] ≥ +0.7 (so-called r-II stars) are believed to have formed in an extremely neutron-rich environment in which a rare astrophysical event (e.g., a neutron-star merger) occurred. This scenario is supported by the existence of an ultra-faint dwarf galaxy, Reticulum II, where most of the stars are highly enhanced in…
Target-of-Opportunity Observation Detectability of Kilonovae with WFST
Dai, Zi-Gao; Zhao, Wen; Liu, Zheng-Yan +4 more
Kilonovae are approximately thermal transients, produced by the mergers of binary neutron stars (BNSs) and neutron star (NS)-black hole binaries. As the optical counterpart of the gravitational-wave event GW170817, AT2017gfo is the first kilonova detected with smoking-gun evidence. Its observation offers vital information for constraining the Hubb…