Search Publications
A Perfect Starburst Cluster made in One Go: The NGC 3603 Young Cluster
Kroupa, Pavel; Banerjee, Sambaran
Understanding how distinct, near-spherical gas-free clusters of very young, massive stars shape out of vast, complex clouds of molecular hydrogen is one of the biggest challenges in astrophysics. A popular thought dictates that a single gas cloud fragments into many newborn stars which, in turn, energize and rapidly expel the residual gas to form …
Extended X-Ray Emission from a Quasar-driven Superbubble
Greene, Jenny E.; Zakamska, Nadia L.; Comerford, Julia M. +2 more
We present observations of extended, 20 kpc scale soft X-ray gas around a luminous obscured quasar hosted by an ultraluminous infrared galaxy caught in the midst of a major merger. The extended X-ray emission is well fit as a thermal gas with a temperature of kT ≈280 eV and a luminosity of L X ≈ 1042 erg s-1 and is…
Extreme Gas Fractions in Clumpy, Turbulent Disk Galaxies at z ~ 0.1
Glazebrook, Karl; Obreschkow, Danail; Abraham, Roberto G. +8 more
In this Letter, we report the discovery of CO fluxes, suggesting very high gas fractions in three disk galaxies seen in the nearby universe (z ~ 0.1). These galaxies were investigated as part of the DYnamics of Newly Assembled Massive Objects (DYNAMO) survey. High-resolution Hubble Space Telescope imaging of these objects reveals the presence of l…
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 …