Search Publications
Stellar Evolution in Real Time: Models Consistent with the Direct Observation of a Thermal Pulse in T Ursae Minoris
Joyce, Meridith; Molnár, László; Kiss, László L.
Most aspects of stellar evolution proceed far too slowly to be directly observable in a single star on human timescales. The thermally pulsing asymptotic giant branch (AGB) is one exception. The combination of state-of-the-art modeling techniques with data assimilated from observations collected by amateur astronomers over many decades provide, fo…
A Faint Halo Star Cluster Discovered in the Blanco Imaging of the Southern Sky Survey
Bechtol, K.; Allam, S.; Kuropatkin, N. +14 more
We present the discovery of a faint, resolved stellar system, BLISS J0321+0438 (BLISS 1), found in Dark Energy Camera data from the first observing run of the Blanco Imaging of the Southern Sky (BLISS) survey. BLISS J0321+0438 (BLISS 1) is located at ({α }2000,{δ }2000)=(177\buildrel{\circ}\over{.} 511,-41\buildrel{\circ}\ove…
Detection of a White Dwarf Companion to a Blue Straggler Star in the Outskirts of Globular Cluster NGC 5466 with the Ultraviolet Imaging Telescope (UVIT)
Stetson, Peter B.; Sahu, Snehalata; Côté, Patrick +8 more
We report the discovery of a hot white dwarf (WD) companion to a blue straggler star (BSS) in the globular cluster (GC) NGC 5466, based on observations from the Ultra-Violet Imaging Telescope (UVIT) on board AstroSat. The Spectral Energy Distribution (SED) of the Far-UV detected BSS NH 84 was constructed by combining the flux measurements from fou…
Galactic Gas Flows from Halo to Disk: Tomography and Kinematics at the Milky Way’s Disk-Halo Interface
Prochaska, J. Xavier; Werk, Jessica K.; O'Meara, John M. +4 more
We present a novel absorption-line survey using 54 blue horizontal branch stars in the Milky Way halo as background sources for detecting gas flows at the disk-halo interface. Distance measurements to high-latitude (b > 60°) background stars at 3.1-13.4 kpc, combined with unprecedented spatial sampling and spectral resolution, allow us to exami…
Discovery of a Double Blue Straggler Sequence in M15: New Insight into the Core-collapse Process
Knigge, C.; Dalessandro, E.; Beccari, G. +8 more
In this paper we report the discovery of a double blue straggler star (BSS) sequence in the core of the core-collapsed cluster M15 (NGC 7078). We performed a detailed photometric analysis of the extremely dense core of the cluster using a set of images secured with the Advanced Camera for Survey in the High Resolution Channel mode on board the Hub…
A Pulsar Wind Nebula Embedded in the Kilonova AT 2017gfo Associated with GW170817/GRB 170817A
Liu, Tong; Lin, Da-Bin; Liang, En-Wei +5 more
The first detected gravitational wave GW170817 from a binary neutron star merger is associated with an important optical transient AT 2017gfo, which is a direct observation of kilonova. Recent observations suggest that the remnant compact object of the binary neutron star merger associated with GW170817/GRB 170817A may be a stable long-lived magne…
SPIRITS Catalog of Infrared Variables: Identification of Extremely Luminous Long Period Variables
Gehrz, R. D.; Bally, J.; Kasliwal, M. M. +12 more
We present a catalog of 417 luminous infrared variable stars with periods exceeding 250 days. These were identified in 20 nearby galaxies by the ongoing SPitzer InfraRed Intensive Transients Survey survey with the Spitzer Space Telescope. Of these, 359 variables have M [4.5] (phase-weighted mean magnitudes) fainter than -12 and periods …
Energetic Electron Acceleration in Unconfined Reconnection Jets
Xu, Y.; Zhang, Y.; Chen, G. +5 more
Magnetic reconnection in astronomical objects such as solar corona and the Earth’s magnetotail theoretically produces a fast jet toward the object (known as a confined jet as it connects to the object through magnetic field lines) and a fast jet departing the object (known as an unconfined jet as it propagates freely in space). So far, energetic e…
Impacts of EUV Wavefronts on Coronal Structures in Homologous Coronal Mass Ejections
Wang, Yuming; Shen, Chenglong; Liu, Rui +1 more
Large-scale propagating fronts are frequently observed during solar eruptions, yet whether or not they are waves is an open question, partly because the propagation is modulated by coronal structures, whose magnetic fields we still cannot measure. However, when a front impacts coronal structures, an opportunity arises for us to look into the magne…
High-resolution Near-infrared Spectroscopy of HD 100546. IV. Orbiting Companion Disappears on Schedule
Najita, Joan R.; Brittain, Sean D.; Carr, John S.
HD 100546 is a Herbig Ae/Be star surrounded by a disk with a large central region that is cleared of gas and dust (i.e., an inner hole). High-resolution near-infrared spectroscopy reveals a rich emission spectrum of fundamental rovibrational CO emission lines whose time variable properties point to the presence of an orbiting companion within the …