Search Publications
The Evolution and Physical Parameters of WN3/O3s: A New Type of Wolf-Rayet Star
Massey, Philip; Hillier, D. John; Morrell, Nidia +1 more
As part of a search for Wolf-Rayet (WR) stars in the Magellanic Clouds, we have discovered a new type of WR star in the Large Magellanic Cloud (LMC). These stars have both strong emission lines, as well as He II and Balmer absorption lines and spectroscopically resemble a WN3 and O3V binary pair. However, they are visually too faint to be WN3+O3V …
The 2014 X-Ray Minimum of η Carinae as Seen by Swift
Gull, T. R.; Corcoran, M. F.; Madura, T. I. +10 more
We report on Swift X-ray Telescope observations of Eta Carinae (η Car), an extremely massive, long-period, highly eccentric binary obtained during the 2014.6 X-ray minimum/periastron passage. These observations show that η Car may have been particularly bright in X-rays going into the X-ray minimum state, while the duration of the 2014 X-ray minim…
The Origin of the Iron-rich Knot in Tycho’s Supernova Remnant
Petre, Robert; Yamaguchi, Hiroya; Hughes, John P. +5 more
X-ray observations of supernova remnants (SNRs) allow us to investigate the chemical inhomogeneity of ejecta, offering unique insight into the nucleosynthesis in supernova explosions. Here we present detailed imaging and spectroscopic studies of the “Fe knot” located along the eastern rim of the Type Ia SNR Tycho (SN 1572) using Suzaku and Chandra…
The Impact of the Group Environment on the O VI Circumgalactic Medium
Charlton, Jane C.; Kacprzak, Glenn G.; Churchill, Christopher W. +3 more
We present a study comparing O VI λλ1031, 1037 doublet absorption found toward group galaxy environments to that of isolated galaxies. The O VI absorption in the circumgalactic medium (CGM) of isolated galaxies has been studied previously by the “Multiphase Galaxy Halos” survey, where the kinematics and absorption properties of the CGM have been i…
Doppler Shift Oscillations from a Hot Line Observed by IRIS
Huang, Y.; Li, D.; Zhang, Q. M. +4 more
We present a detailed investigation of the Doppler shift oscillations in a hot loop during an M7.1 flare on 2014 October 27 observed by the Interface Region Imaging Spectrograph. The periodic oscillations are observed in the Doppler shift of Fe xxi 1354.09 Å (log T∼ 7.05), and the dominant period is about 3.1 minutes. However, such 3.1 minute osci…
Strongly Misaligned Triple System in SR 24 Revealed by ALMA
Fernández-López, M.; Zapata, L. A.; Gabbasov, R.
We report the detection of the 1.3 mm continuum and the molecular emission of the disks of the young triple system SR24 by analyzing ALMA (The Atacama Large Millimeter/Submillimter Array) subarcsecond archival observations. We estimate the mass of the disks (0.025 M ⊙ and 4 × 10-5 M ⊕ for SR24S and SR24N, respectiv…
The Dense Molecular Gas and Nuclear Activity in the ULIRG IRAS 13120-5453
Treister, E.; Armus, L.; van der Werf, P. +12 more
We present new Atacama Large Millimeter/submillimeter Array Band 7 (∼340 GHz) observations of the dense gas tracers HCN, HCO+, and CS in the local, single-nucleus, ultraluminous infrared galaxy IRAS 13120-5453. We find centrally enhanced HCN (4-3) emission, relative to HCO+ (4-3), but do not find evidence for radiative pumpin…
Hard X-Ray-selected AGNs in Low-mass Galaxies from the NuSTAR Serendipitous Survey
Harrison, F. A.; Stern, D.; Alexander, D. M. +14 more
We present a sample of 10 low-mass active galactic nuclei (AGNs) selected from the 40-month Nuclear Spectroscopic Telescope Array (NuSTAR) serendipitous survey. The sample is selected to have robust NuSTAR detections at 3{--}24 {keV}, to be at z< 0.3, and to have optical r-band magnitudes at least 0.5 mag fainter than an {L}\star ga…
The Plasma Parameters and Geometry of Cool and Warm Active Region Loops
Fu, Hui; Madjarska, Maria S.; Li, Bo +5 more
How the solar corona is heated to high temperatures remains an unsolved mystery in solar physics. In the present study we analyze observations of 50 whole active region loops taken with the Extreme-ultraviolet Imaging Spectrometer on board the Hinode satellite. Eleven loops were classified as cool loops (<1 MK) and 39 as warm loops (1-2 MK). We…
Massive Star Cluster Formation and Destruction in Luminous Infrared Galaxies in GOALS
Kim, D. -C.; Surace, J. A.; Inami, H. +17 more
We present the results of a Hubble Space Telescope ACS/HRC FUV, ACS/WFC optical study into the cluster populations of a sample of 22 Luminous Infrared Galaxies in the Great Observatories All-Sky LIRG Survey. Through integrated broadband photometry, we have derived ages and masses for a total of 484 star clusters contained within these systems. Thi…