Search Publications
Revealing Asymmetries in the HD 181327 Debris Disk: A Recent Massive Collision or Interstellar Medium Warping
Stark, Christopher C.; Weinberger, Alycia J.; Debes, John H. +4 more
New multi-roll coronagraphic images of the HD 181327 debris disk obtained using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope reveal the debris ring in its entirety at high signal-to-noise ratio and unprecedented spatial resolution. We present and apply a new multi-roll image processing routine to identify and furthe…
CARMA Large Area Star Formation Survey: Structure and Kinematics of Dense Gas in Serpens Main
Kwon, Woojin; Rosolowsky, Erik; Kauffmann, Jens +21 more
We present observations of N2H+ (J = 1 → 0), HCO+ (J = 1 → 0), and HCN (J = 1 → 0) toward the Serpens Main molecular cloud from the CARMA Large Area Star Formation Survey (CLASSy). We mapped 150 arcmin2 of Serpens Main with an angular resolution of ~7''. The gas emission is concentrated in two subcluster…
Five Debris Disks Newly Revealed in Scattered Light from the Hubble Space Telescope NICMOS Archive
Schneider, Glenn; Hines, Dean C.; Perrin, Marshall D. +12 more
We have spatially resolved five debris disks (HD 30447, HD 35841, HD 141943, HD 191089, and HD 202917) for the first time in near-infrared scattered light by reanalyzing archival Hubble Space Telescope (HST)/NICMOS coronagraphic images obtained between 1999 and 2006. One of these disks (HD 202917) was previously resolved at visible wavelengths usi…
Cold and Warm Atomic Gas around the Perseus Molecular Cloud. I. Basic Properties
Murray, Claire E.; Stanimirović, Snežana; Lee, Min-Young +2 more
Using the Arecibo Observatory, we have obtained neutral hydrogen (HI) absorption and emission spectral pairs in the direction of 26 background radio continuum sources in the vicinity of the Perseus molecular cloud. Strong absorption lines were detected in all cases, allowing us to estimate spin temperature (Ts ) and optical depth for 10…
The Supernova Progenitor Mass Distributions of M31 and M33: Further Evidence for an Upper Mass Limit
Dolphin, Andrew E.; Williams, Benjamin F.; Gilbert, Karoline M. +5 more
Using Hubble Space Telescope photometry to measure star formation histories, we age-date the stellar populations surrounding supernova remnants (SNRs) in M31 and M33. We then apply stellar evolution models to the ages to infer the corresponding masses for their supernova progenitor stars. We analyze 33 M33 SNR progenitors and 29 M31 SNR progenitor…
An Accreting White Dwarf near the Chandrasekhar Limit in the Andromeda Galaxy
Cenko, S. Bradley; Kong, Albert K. H.; Perley, Daniel A. +13 more
The intermediate Palomar Transient Factory (iPTF) detection of the most recent outburst of the recurrent nova (RN) system RX J0045.4+4154 in the Andromeda galaxy has enabled the unprecedented study of a massive (M > 1.3 M ⊙) accreting white dwarf (WD). We detected this nova as part of the near-daily iPTF monitoring of M31 to a depth …
The Host Galaxies of Fast-ejecta Core-collapse Supernovae
Filippenko, Alexei V.; Kelly, Patrick L.; Modjaz, Maryam +1 more
Spectra of broad-lined Type Ic supernovae (SNe Ic-BL), the only kind of SN observed at the locations of long-duration gamma-ray bursts (LGRBs), exhibit wide features indicative of high ejecta velocities (~0.1c). We study the host galaxies of a sample of 245 low-redshift (z < 0.2) core-collapse SNe, including 17 SNe Ic-BL, discovered by galaxy-u…
Detection of Supersonic Downflows and Associated Heating Events in the Transition Region above Sunspots
Golub, L.; Tian, H.; De Pontieu, B. +18 more
Interface Region Imaging Spectrograph data allow us to study the solar transition region (TR) with an unprecedented spatial resolution of 0.''33. On 2013 August 30, we observed bursts of high Doppler shifts suggesting strong supersonic downflows of up to 200 km s-1 and weaker, slightly slower upflows in the spectral lines Mg II h and k,…
Physical Interpretation of the Angle-dependent Magnetic Helicity Spectrum in the Solar Wind: The Nature of Turbulent Fluctuations near the Proton Gyroradius Scale
Klein, Kristopher G.; TenBarge, Jason M.; Howes, Gregory G. +1 more
Motivated by recent observations of distinct parallel and perpendicular signatures in magnetic helicity measurements segregated by wave period and angle between the local magnetic field and the solar wind velocity, this paper undertakes a comparison of three intervals of Ulysses data with synthetic time series generated from a physically motivated…
Ground Level Enhancement in the 2014 January 6 Solar Energetic Particle Event
Gopalswamy, N.; Davila, J. M.; Yashiro, S. +4 more
We present a study of the 2014 January 6 solar energetic particle event which produced a small ground level enhancement (GLE), making it the second GLE of this unusual solar cycle 24. This event was primarily observed by the South Pole neutron monitors (increase of ~2.5%) while a few other neutron monitors recorded smaller increases. The associate…