Search Publications
The Location of Solar Metric Type II Radio Bursts with Respect to the Associated Coronal Mass Ejections
Ramesh, R.; Kathiravan, C.; Gopalswamy, N. +2 more
Forty-one solar type II radio bursts located close to the solar limb (projected radial distance r >~ 0.8 R ⊙) were observed at 109 MHz by the radioheliograph at the Gauribidanur observatory near Bangalore during the period 1997-2007. The positions of the bursts were compared with the estimated location of the leading edge (LE) of the…
A Type Ia Supernova at Redshift 1.55 in Hubble Space Telescope Infrared Observations from CANDELS
Ferguson, Henry C.; Grogin, Norman A.; Weiner, Benjamin J. +23 more
We report the discovery of a Type Ia supernova (SN Ia) at redshift z = 1.55 with the infrared detector of the Wide Field Camera 3 (WFC3-IR) on the Hubble Space Telescope (HST). This object was discovered in CANDELS imaging data of the Hubble Ultra Deep Field and followed as part of the CANDELS+CLASH Supernova project, comprising the SN search comp…
The Three-dimensional Distribution of Dust in NGC 891
Bershady, Matthew A.; Schechtman-Rook, Andrew; Wood, Kenneth
We produce three-dimensional Monte Carlo radiative transfer models of the edge-on spiral galaxy NGC 891, a fast-rotating galaxy thought to be an analog to the Milky Way. The models contain realistic spiral arms and a fractal distribution of clumpy dust. We fit our models to Hubble Space Telescope images corresponding to the B and I bands, using sh…
Discovery and Early Multi-wavelength Measurements of the Energetic Type Ic Supernova PTF12gzk: A Massive-star Explosion in a Dwarf Host Galaxy
Vanderburg, Andrew; Filippenko, Alexei V.; Cenko, S. Bradley +46 more
We present the discovery and extensive early-time observations of the Type Ic supernova (SN) PTF12gzk. Our light curves show a rise of 0.8 mag within 2.5 hr. Power-law fits (f(t)vprop(t - t 0) n ) to these data constrain the explosion date to within one day. We cannot rule out a quadratic fireball model, but higher values of …
Observations of the near- to Mid-infrared Unidentified Emission Bands in the Interstellar Medium of the Large Magellanic Cloud
Onaka, Takashi; Sakon, Itsuki; Kaneda, Hidehiro +3 more
We present the results of near- to mid-infrared slit spectroscopic observations (2.55-13.4 µm) of the diffuse emission toward nine positions in the Large Magellanic Cloud with the infrared camera on board AKARI. The target positions are selected to cover a wide range of the intensity of the incident radiation field. The unidentified infrared…
Supernova Remnant Progenitor Masses in M31
Dolphin, Andrew E.; Williams, Benjamin F.; Gilbert, Karoline M. +5 more
Using Hubble Space Telescope photometry, we age-date 59 supernova remnants (SNRs) in the spiral galaxy M31 and use these ages to estimate zero-age main-sequence masses (M ZAMS) for their progenitors. To accomplish this, we create color-magnitude diagrams (CMDs) and employ CMD fitting to measure the recent star formation history of the r…
COSMOS: Stochastic Bias from Measurements of Weak Lensing and Galaxy Clustering
Massey, Richard; Kneib, Jean-Paul; Rhodes, Jason +6 more
In the theory of structure formation, galaxies are biased tracers of the underlying matter density field. The statistical relation between galaxy and matter density field is commonly referred to as galaxy bias. In this paper, we test the linear bias model with weak-lensing and galaxy clustering measurements in the 2 deg2 COSMOS field. W…
It's Alive! The Supernova Impostor 1961V
Van Dyk, Schuyler D.; Matheson, Thomas
Reports of the death of the precursor of supernova (SN) 1961V in NGC 1058 are exaggerated. Consideration of the best astrometric data shows that the star, known as "Object 7," lies at the greatest proximity to SN 1961V and is the likely survivor of the "SN impostor" super-outburst. SN 1961V does not coincide with a neighboring radio source and is …
Physical Properties of the Narrow-line Region of Low-mass Active Galaxies
Ho, Luis C.; Barth, Aaron J.; Greene, Jenny E. +1 more
We present spectroscopic observations of 27 active galactic nuclei (AGNs) with some of the lowest black hole (BH) masses known. We use the high spectral resolution and small aperture of our Keck data, taken with the Echellette Spectrograph and Imager, to isolate the narrow-line regions (NLRs) of these low-mass BHs. We investigate their emission-li…
The Cluster of Blue Stars Surrounding the M31 Nuclear Black Hole
Green, Richard F.; Kormendy, John; Lauer, Tod R. +2 more
We obtained U 330- and B-band images of the M31 nucleus using the High Resolution Camera of the Advanced Camera for Surveys on board the Hubble Space Telescope (HST). The spatial resolution in the U 330 band, 0farcs03 FWHM, or 0.1 pc at M31, is sufficient to resolve the outskirts of the compact cluster (P3) of UV-bright stars…