Search Publications
Volatile-rich Circumstellar Gas in the Unusual 49 Ceti Debris Disk
Weinberger, Alycia J.; Roberge, Aki; Grady, Carol A. +2 more
We present Hubble Space Telescope Space Telescope Imaging Spectrograph far-UV spectra of the edge-on disk around 49 Ceti, one of the very few debris disks showing submillimeter CO emission. Many atomic absorption lines are present in the spectra, most of which arise from circumstellar gas lying along the line-of-sight to the central star. We deter…
Detection of Neutral Phosphorus in the Near-ultraviolet Spectra of Late-type Stars
Roederer, Ian U.; Frebel, Anna; Toller, Elizabeth +2 more
We report the detection of several absorption lines of neutral phosphorus (P, Z = 15) in archival near-ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. We derive phosphorus abundances or interesting upper limits in 14 late-type stars with metallicities spanning -3.8 < [Fe/H] <-0.…
Spectral Modeling of the Charge-exchange X-Ray Emission from M82
Zhou, Xin; Wang, Q. Daniel; Foster, Adam R. +3 more
It has been proposed that the charge-exchange (CX) process at the interface between hot and cool interstellar gases could contribute significantly to the observed soft X-ray emission in star-forming galaxies. We analyze the XMM-Newton/reflection grating spectrometer (RGS) spectrum of M82 using a newly developed CX model combined with a single-temp…
The UBV Color Evolution of Classical Novae. I. Nova-giant Sequence in the Color-Color Diagram
Kato, Mariko; Hachisu, Izumi
We identified a general course of classical nova outbursts in the B - V versus U - B color-color diagram. It is reported that novae show spectra similar to those of A-F supergiants near optical light maximum. However, they do not follow the supergiant sequence in the color-color diagram, neither the blackbody nor the main-sequence sequence. Instea…
The Onset of Massive Star Formation: The Evolution of Temperature and Density Structure in an Infrared Dark Cloud
Ginsburg, Adam; Battersby, Cara; Bally, John +3 more
We present new NH3 (1, 1), (2, 2), and (4, 4) observations from the Karl G. Jansky Very Large Array compiled with work in the literature to explore the range of conditions observed in young, massive star-forming regions. To sample the effects of evolution independent from those of distance/resolution, abundance, and large-scale environm…
Supernova Remnant W49B and Its Environment
Zhu, H.; Tian, W. W.; Zuo, P.
We study gamma-ray supernova remnant (SNR) W49B and its environment using recent radio and infrared data. Spitzer Infrared Spectrograph low resolution data of W49B shows shocked excitation lines of H2 (0,0) S(0)-S(7) from the SNR-molecular cloud interaction. The H2 gas is composed of two components with temperatures of ~260 K…
Discovery of Time Variation of the Intensity of Molecular Lines in IRC+10216 in the Submillimeter and Far-Infrared Domains
Teyssier, D.; García-Lario, P.; Barlow, M. J. +12 more
We report on the discovery of strong intensity variations in the high rotational lines of abundant molecular species toward the archetypical circumstellar envelope of IRC+10216. The observations have been carried out with the Heterodyne Instrument for the Far-Infrared (HIFI) instrument on board Herschel and with the IRAM30 m telescope. They cover …
Comparing M31 and Milky Way Satellites: The Extended Star Formation Histories of Andromeda II and Andromeda XVI
Ferguson, Henry C.; McQuinn, Kristen B. W.; Dolphin, Andrew E. +16 more
We present the first comparison between the lifetime star formation histories (SFHs) of M31 and Milky Way (MW) satellites. Using the Advanced Camera for Surveys on board the Hubble Space Telescope, we obtained deep optical imaging of Andromeda II (And II; MV = -12.0 log(M sstarf/M ⊙) ~ 6.7) and Andromeda XVI (And X…
Star-cluster Mass and Age Distributions of Two Fields in M83 Based on HST/WFC3 Observations
Calzetti, Daniela; Whitmore, Bradley C.; Chandar, Rupali +1 more
We study star clusters in two fields in the nearby spiral galaxy M83 using broadband and narrowband optical imaging taken with the Wide Field Camera 3 onboard the Hubble Space Telescope. We present results on the basis of several different catalogs of star clusters in inner and outer fields, and we conclude that different methods of selection do n…
AKARI IRC 2.5-5 µm Spectroscopy of Infrared Galaxies over a Wide Luminosity Range
Nakagawa, Takao; Shirahata, Mai; Oyabu, Shinki +4 more
We present the result of a systematic infrared 2.5-5 µm spectroscopic study of 22 nearby infrared galaxies over a wide infrared luminosity range (1010 L ⊙ < L IR < 1013 L ⊙) obtained from the AKARI Infrared Camera (IRC). The unique band of the AKARI IRC spectroscopy enables us to a…