Search Publications
An Inverse Compton Scattering Origin of X-Ray Flares from Sgr A*
Genzel, R.; Heinke, C. O.; Grosso, N. +6 more
The X-ray and near-IR emission from Sgr A* is dominated by flaring, while a quiescent component dominates the emission at radio and submillimeter (sub-mm) wavelengths. The spectral energy distribution of the quiescent emission from Sgr A* peaks at sub-mm wavelengths and is modeled as synchrotron radiation from a thermal population of electrons in …
The Herschel Virgo Cluster Survey. XI. Environmental effects on molecular gas and dust in spiral disks
Ciesla, L.; Bianchi, S.; Fritz, J. +19 more
Aims: We investigate the dust-to-gas mass ratio and the environmental effects on the various components of the interstellar medium for a spatially resolved sample of Virgo spirals.
Methods: We have used the IRAM-30 m telescope to map over their full extent NGC 4189, NGC 4298, NGC 4388, and NGC 4299 in the 12CO(1-0) and the
Comparison between theory and observation of the frequency sweep rates of equatorial rising tone chorus
Li, W.; Tao, X.; Bortnik, J. +2 more
Theoretical predictions for chorus frequency sweep rates by Helliwell and Trakhtengerts are compared with observations from the THEMIS satellites and a previously published dataset from the Cluster satellites. We first extend the theories to use a general magnetic field model to include the effects of magnetic local time and geomagnetic activity, …
Herschel Search for O2 toward the Orion Bar
Li, Di; van Dishoeck, Ewine F.; Encrenaz, Pierre +15 more
We report the results of a search for molecular oxygen (O2) toward the Orion Bar, a prominent photodissociation region at the southern edge of the H II region created by the luminous Trapezium stars. We observed the spectral region around the frequency of the O2 NJ = 33-12 transition at 487 GH…
XMM-Newton View of Swift J1834.9-0846 and Its Magnetar Wind Nebula
Kouveliotou, C.; Pavlov, G. G.; Göǧüş, E. +3 more
We report on the analysis of two XMM-Newton observations of the recently discovered soft gamma repeater Swift J1834.9-0846, taken in 2005 September and one month after the source went into outburst on 2011 August 7. We performed timing and spectral analyses on the point source as well as on the extended emission. We find that the source period is …
A 7 mm line survey of the shocked and disrupted molecular gas towards the W28 field TeV gamma-ray sources
Rowell, G.; Fukui, Y.; Burton, M. G. +4 more
We present 7 mm Mopra observations of the dense molecular gas towards the W28 supernova remnant (SNR) field, following a previous 12 mm line survey of this region. These observations take advantage of the 7 mm beam size to probe the dense and disrupted gas in the region at ∼1 arcmin scales. Our observations are focused towards the north-eastern (N…
A Treasury Study of Star-forming Regions in the Local Group. I. HST Photometry of Young Populations in Six Dwarf Galaxies
Massey, Philip; Bianchi, Luciana; Olsen, K. A. G. +2 more
We present a comprehensive study of young stellar populations in six dwarf galaxies in or near the Local Group: Phoenix, Pegasus, Sextans A, Sextans B, WLM, and NGC 6822. Their star-forming regions, selected from GALEX wide-field far-UV imaging, were imaged (at sub-pc resolution) with the WFPC2 camera on board the Hubble Space Telescope (HST) in s…
Supernova remnants and candidates detected in the XMM-Newton M 31 large survey
Stiele, H.; Pietsch, W.; Haberl, F. +5 more
Context. We present the analysis of supernova remnants (SNRs) and candidates in M 31 identified in the XMM-Newton large programme survey of M 31. Supernova remnants are among the brightest X-ray sources in a galaxy. They are good indicators of the recent star-formation activities of galaxies and the interstellar environment in which they evolve. <…
Detection of sub-kilometer craters in high resolution planetary images using shape and texture features
Stepinski, Tomasz F.; Bandeira, Lourenço; Ding, Wei
Counting craters is a paramount tool of planetary analysis because it provides relative dating of planetary surfaces. Dating surfaces with high spatial resolution requires counting a very large number of small, sub-kilometer size craters. Exhaustive manual surveys of such craters over extensive regions are impractical, sparking interest in designi…
Exploring the Diversity of Groups at 0.1 < z < 0.8 with X-Ray and Optically Selected Samples
Mulchaey, John S.; Connelly, J. L.; Balogh, Michael L. +8 more
We present the global group properties of two samples of galaxy groups containing 39 high-quality X-ray-selected systems and 38 optically (spectroscopically) selected systems in coincident spatial regions at 0.12 < z < 0.79. The total mass range of the combined sample is ~(1012-5) × 1014 M ⊙. Only nine optica…