Search Publications
Evidence for episodic alluvial fan formation in far western Terra Tyrrhena, Mars
Chojnacki, Matthew; Williams, Rebecca M. E.; Seelos, Kimberly D. +4 more
A Late Noachian-aged alluvial fan complex within Harris Crater in far western Terra Tyrrhena, Mars, is comprised of two well-defined source regions and associated discrete depositional lobes. Three fan units were recognized based on common morphological characteristics, thermal properties and spectral signatures. Although the entire fan complex ha…
The low-mass initial mass function in the Orion nebula cluster based on HST/NICMOS III imaging
Robberto, M.; Andersen, M.; Meyer, M. R. +2 more
We present deep HST/NICMOS Camera 3 F110W and F160W imaging of a 26' × 33', corresponding to 3.1 pc × 3.8 pc, non-contiguous field towards the Orion nebula cluster (ONC). The main aim is to determine the ratio of low-mass stars to brown dwarfs for the cluster as a function of radius out to a radial distance of 1.5 pc. The sensitivity of the data o…
Relation Between the 3D-Geometry of the Coronal Wave and Associated CME During the 26 April 2008 Event
Temmer, M.; Veronig, A. M.; Gopalswamy, N. +1 more
We study the kinematical characteristics and 3D geometry of a large-scale coronal wave that occurred in association with the 26 April 2008 flare-CME event. The wave was observed with the EUVI instruments aboard both STEREO spacecraft (STEREO-A and STEREO-B) with a mean speed of ∼ 240 km s−1. The wave is more pronounced in the eastern pr…
The Redshift and Nature of AzTEC/COSMOS 1: A Starburst Galaxy at z = 4.6
Kneib, J. -P.; Berta, S.; Lutz, D. +36 more
Based on broadband/narrowband photometry and Keck DEIMOS spectroscopy, we report a redshift of z = 4.64+0.06 -0.08 for AzTEC/COSMOS 1, the brightest submillimeter galaxy (SMG) in the AzTEC/COSMOS field. In addition to the COSMOS-survey X-ray to radio data, we report observations of the source with Herschel/PACS (100, 160 &mic…
The Deepest Hubble Space Telescope Color-Magnitude Diagram of M32. Evidence for Intermediate-age Populations
Monachesi, Antonela; Lauer, Tod R.; Dressler, Alan +4 more
We present the deepest optical color-magnitude diagram (CMD) to date of the local elliptical galaxy M32. We have obtained F435W and F555W photometries based on Hubble Space Telescope (HST) Advanced Camera for Surveys/High-Resolution Channel images for a region 110'' from the center of M32 (F1) and a background field (F2) about 320'' away from M32 …
Black Holes in Bulgeless Galaxies: An XMM-Newton Investigation of NGC 3367 and NGC 4536
Cheung, C. C.; Eracleous, Michael; Satyapal, S. +3 more
The vast majority of optically identified active galactic nuclei (AGNs) in the local universe reside in host galaxies with prominent bulges, supporting the hypothesis that black hole formation and growth is fundamentally connected to the buildup of galaxy bulges. However, recent mid-infrared spectroscopic studies with Spitzer of a sample of optica…
Evidence for Black Hole Growth in Local Analogs to Lyman Break Galaxies
Heckman, Timothy M.; Hornschemeier, Ann; Overzier, Roderik A. +3 more
We have used XMM-Newton to observe six Lyman break analogs (LBAs): members of the rare population of local galaxies that have properties that are very similar to distant Lyman break galaxies. Our six targets were specifically selected because they have optical emission-line properties that are intermediate between starbursts and Type 2 (obscured) …
INTEGRAL, Swift, and RXTE observations of the 518 Hz accreting transient pulsar Swift J1749.4-2807
Campana, S.; Stella, L.; Belloni, T. +7 more
Context. The burst-only source Swift J1749.4-2807 was discovered in a high X-ray-active state, during an INTEGRAL observations of the Galactic bulge on 2010 April 10. Pulsations at 518 Hz were discovered in the RXTE data, confirming previous suggestions of possible associations between burst-only sources and accreting millisecond X-ray pulsars. Th…
A Coherent Timing Solution for the Nearby, Thermally Emitting Isolated Neutron Star RX J0420.0-5022
van Kerkwijk, M. H.; Kaplan, D. L.
We present a phase-coherent timing solution for RX J0420.0-5022, the coolest (kT ~= 45 eV) and fastest-spinning (P = 3.45 s) of the seven so-called isolated neutron stars (INSs). Using 14 observations with the XMM-Newton spacecraft in 2010 and 2011, we were able to measure a spin-down rate \dot{\nu }=(-2.3+/- 0.2)\times 10^{-15}\,{\,Hz\,s}^{-1} (\…
67P/Churyumov-Gerasimenko activity evolution during its last perihelion before the Rosetta encounter
Lara, L. M.; Rodrigo, R.; Ip, W. -H. +1 more
Context. The comet 67P/Churyumov-Gerasimenko, target of the Rosetta Mission (ESA) was monitored from January to April 2009 during its last perihelion passage before the Rosetta spacecraft encounters the comet nucleus in May 2014. Photometric data were obtained only from January 25 to March 19, 2009 and they were used to monitor the comet gas and d…