Search Publications
Lifetimes and Oscillator Strengths for Ultraviolet Transitions in Singly Ionized Lead
Federman, S. R.; Ritchey, A. M.; Irving, R. E. +5 more
We present the results of lifetime measurements made using beam-foil techniques on levels of astrophysical interest in Pb ii producing lines at 1203.6 Å (6s6p2 {}2{D}3/2) and 1433.9 Å (6{s}26d {}2{D}3/2). We also report the first detection of the Pb ii λ 1203 line in the interstella…
The Bottom-light Present Day Mass Function of the Peculiar Globular Cluster NGC 6535
Zaritsky, Dennis; Halford, Melissa
Dynamical mass calculations have suggested that the Milky Way globular cluster NGC 6535 belongs to a population of clusters with high mass-to-light ratios, possibly due to a bottom-heavy stellar initial mass function (IMF). We use published Hubble Space Telescope data to measure the present day stellar mass function of this cluster within its half…
Anomalous Microwave Emission in HII Regions: Is it Really Anomalous? The Case of RCW 49
Paladini, Roberta; Noriega-Crespo, Alberto; Agliozzo, Claudia +5 more
The detection of an excess of emission at microwave frequencies with respect to the predicted free-free emission has been reported for several Galactic H ii regions. Here, we investigate the case of RCW 49, for which the Cosmic Background Imager tentatively (∼3σ) detected Anomalous Microwave Emission (AME) at 31 GHz on angular scales of 7‧. Using …
Investigating the Nature of IGR J17454-2919 Using X-Ray and Near-infrared Observations
Greiner, J.; Nowak, M. A.; Chaty, S. +7 more
IGR J17454-2919 is a hard X-ray transient discovered by INTEGRAL on 2014 September 27. We report on our 20 ks Chandra observation of the source, performed about five weeks after the discovery, as well as on INTEGRAL and Swift long-term monitoring observations. X-ray broad-band spectra of the source are compatible with an absorbed power law, {{Γ }}…
XMM-Newton Measurement of the Galactic Halo X-Ray Emission using a Compact Shadowing Cloud
Henley, David B.; Shelton, Robin L.; Stancil, Phillip C. +1 more
Observations of interstellar clouds that cast shadows in the soft X-ray background can be used to separate the background Galactic halo emission from the local emission due to solar wind charge exchange (SWCX) and/or the Local Bubble (LB). We present an XMM-Newton observation of a shadowing cloud, G225.60-66.40, that is sufficiently compact that t…
Infrared Spectral Properties of M Giants
Sloan, G. C.; Goes, C.; Ramirez, R. M. +2 more
We observed a sample of 20 M giants with the Infrared Spectrograph on the Spitzer Space Telescope. Most show absorption structure at 6.6-6.8 µm which we identify as water vapor, and in some cases, the absorption extends from 6.4 µm into the SiO band at 7.5 µm. Variable stars show stronger H2O absorption. While the stre…
Submillimeter Observations of CLASH 2882 and the Evolution of Dust in this Galaxy
Staguhn, Johannes; Walter, Fabian; Egami, Eiichi +7 more
Two millimeter observations of the MACS J1149.6+2223 cluster have detected a source that was consistent with the location of the lensed MACS 1149-JD galaxy at z = 9.6. A positive identification would have rendered this galaxy as the youngest dust forming galaxy in the universe. Follow up observation with the AzTEC 1.1 mm camera and the IRAM NOrthe…
Discovery of Five Candidate Analogs for η Carinae in Nearby Galaxies
Sonneborn, G.; Kochanek, C. S.; Stanek, K. Z. +2 more
The late-stage evolution of very massive stars such as η Carinae may be dominated by episodic mass ejections that may later lead to Type II superluminous supernova (SLSN-II; e.g., SN 2006gy). However, as long as η Car is one of a kind, it is nearly impossible to quantitatively evaluate these possibilities. Here, we announce the discovery of five o…
Ultraviolet ISM Diagnostics for Star-forming Galaxies. I. Tracers of Metallicity and Extinction
Leitherer, Claus; Danforth, Charles W.; Zetterlund, Erika +1 more
We have observed a sample of 14 nearby (z∼ 0.03) star-forming blue compact galaxies (BCGs) in the rest-frame far-UV (∼1150-2200 Å) using the Cosmic Origins Spectrograph on the Hubble Space Telescope. We have also generated a grid of stellar population synthesis models using the Starburst99 evolutionary synthesis code, allowing us to compare observ…
Environment of the Submillimeter-bright Massive Starburst HFLS3 at z ~ 6.34
Pérez-Fournon, I.; Ivison, R. J.; Clements, D. L. +28 more
We describe the search for Lyman break galaxies (LBGs) near the submillimeter-bright starburst galaxy HFLS3 at z = 6.34 and a study on the environment of this massive galaxy during the end of reionization. We performed two independent selections of LBGs on images obtained with the Gran Telescopio Canarias (GTC) and the Hubble Space Telescope (HST)…