Search Publications
Lyα and UV Sizes of Green Pea Galaxies
Leitherer, Claus; Wofford, Aida; Malhotra, Sangeeta +4 more
Green Peas are nearby analogs of high-redshift Lyα-emitting galaxies (LAEs). To probe their Lyα escape, we study the spatial profiles of Lyα and UV continuum emission of 24 Green Pea galaxies using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope. We extract the spatial profiles of Lyα emission from their 2D COS spectra, and of …
The Rotation-Activity Correlations in K and M Dwarfs. II. New Constraints on the Dynamo Mechanisms in Late-K and M Dwarfs Before and At the Transition to Complete Convection
Mullan, D. J.; Gebran, M.; Houdebine, E. R. +2 more
We study the rotation-activity correlations (RACs) in a sample of stars from spectral type dK4 to dM4. We study RACs using chromospheric data and coronal data. We study the Ca II line surface fluxes-P/\sin I RACs. We fit the RACs with linear homoscedastic and heteroscedastic regression models. We find that these RACs differ substantially from one …
A Hubble Space Telescope Survey for Novae in M87. II. Snuffing out the Maximum Magnitude-Rate of Decline Relation for Novae as a Non-standard Candle, and a Prediction of the Existence of Ultrafast Novae
Welch, D. L.; Lauer, Tod R.; Mikołajewska, Joanna +9 more
The extensive grid of numerical simulations of nova eruptions from the work of Yaron et al. first predicted that some classical novae might significantly deviate from the Maximum Magnitude-Rate of Decline (MMRD) relation, which purports to characterize novae as standard candles. Kasliwal et al. have announced the observational detection of a new c…
Investigating the Origins of Two Extreme Solar Particle Events: Proton Source Profile and Associated Electromagnetic Emissions
Vainio, Rami; Valtonen, Eino; Pohjolainen, Silja +13 more
We analyze the high-energy particle emission from the Sun in two extreme solar particle events in which protons are accelerated to relativistic energies and can cause a significant signal even in the ground-based particle detectors. Analysis of a relativistic proton event is based on modeling of the particle transport and interaction, from a near-…
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…