Search Publications
A VLT/FLAMES Study of the Peculiar Intermediate-age Large Magellanic Cloud Star Cluster NGC 1846. I. Kinematics
Da Costa, G. S.; Yong, D.; Mackey, A. D. +1 more
In this paper we present high-resolution VLT/FLAMES observations of red giant stars in the massive intermediate-age Large Magellanic Cloud star cluster NGC 1846, which, on the basis of its extended main-sequence turnoff (EMSTO), possesses an internal age spread of ≈300 Myr. We describe in detail our target selection and data reduction procedures, …
A Resolved Debris Disk around the Candidate Planet-hosting Star HD 95086
Apai, D.; Pascucci, I.; Ábrahám, P. +11 more
Recently, a new planet candidate was discovered on direct images around the young (10-17 Myr) A-type star HD 95086. The strong infrared excess of the system indicates that, similar to HR8799, β Pic, and Fomalhaut, the star harbors a circumstellar disk. Aiming to study the structure and gas content of the HD 95086 disk, and to investigate its possi…
Tearing the Veil: Interaction of the Orion Nebula with its Neutral Environment
O'Dell, C. R.; van der Werf, Paul P.; Goss, W. M.
We present H I 21 cm observations of the Orion Nebula, obtained with the Karl G. Jansky Very Large Array, at an angular resolution of 7.''2 × 5.''7 and a velocity resolution of 0.77 km s-1. Our data reveal H I absorption in the Veil toward the radio continuum of the H II region, and H I emission arising from the Orion Bar photon-dominat…
What are the Progenitors of Compact, Massive, Quiescent Galaxies at z = 2.3? The Population of Massive Galaxies at z > 3 from NMBS and CANDELS
Marchesini, Danilo; Stefanon, Mauro; Whitaker, Katherine E. +2 more
Using public data from the NEWFIRM Medium-Band Survey (NMBS) and the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS), we investigate the population of massive galaxies at z > 3. The main aim of this work is to identify the potential progenitors of z ~ 2 compact, massive, quiescent galaxies (CMQGs), furthering our unders…
Blind Extraction of an Exoplanetary Spectrum through Independent Component Analysis
Waldmann, I. P.; Tinetti, G.; Yurchenko, S. N. +3 more
Blind-source separation techniques are used to extract the transmission spectrum of the hot-Jupiter HD189733b recorded by the Hubble/NICMOS instrument. Such a "blind" analysis of the data is based on the concept of independent component analysis. The detrending of Hubble/NICMOS data using the sole assumption that nongaussian systematic noise is st…
GOODS-Herschel: Separating High-redshift Active Galactic Nuclei and Star-forming Galaxies Using Infrared Color Diagnostics
Dickinson, Mark; Kirkpatrick, Allison; Valtchanov, Ivan +17 more
We have compiled a large sample of 151 high-redshift (z = 0.5-4) galaxies selected at 24 µm (S 24 > 100 µJy) in the GOODS-N and ECDFS fields for which we have deep Spitzer IRS spectroscopy, allowing us to decompose the mid-infrared spectrum into contributions from star formation and activity in the galactic nuclei. In add…
The Optical Counterpart to the X-Ray Transient IGR J1824-24525 in the Globular Cluster M28
Dalessandro, E.; Beccari, G.; Ferraro, F. R. +2 more
We report on the identification of the optical counterpart to the recently detected INTEGRAL transient IGR J1824-24525 in the Galactic globular cluster M28. From analysis of a multi-epoch Hubble Space Telescope data set, we have identified a strongly variable star positionally coincident with the radio and Chandra X-ray sources associated with the…
Decay-phase Cooling and Inferred Heating of M- and X-class Solar Flares
Ryan, Daniel F.; Chamberlin, Phillip C.; Milligan, Ryan O. +1 more
In this paper, the cooling of 72 M- and X-class flares is examined using GOES/XRS and SDO/EVE. The observed cooling rates are quantified and the observed total cooling times are compared with the predictions of an analytical zero-dimensional hydrodynamic model. We find that the model does not fit the observations well, but does provide a well-defi…
Electron and Proton Acceleration during the First Ground Level Enhancement Event of Solar Cycle 24
Li, C.; Sun, L. P.; Firoz, Kazi A. +1 more
High-energy particles were recorded by near-Earth spacecraft and ground-based neutron monitors (NMs) on 2012 May 17. This event was the first ground level enhancement (GLE) of solar cycle 24. In this study, we try to identify the acceleration source(s) of solar energetic particles by combining in situ particle measurements from the WIND/3DP, GOES …
Chromospheric Evaporation in Solar Flare Loop Strands Observed with the Extreme-ultraviolet Imaging Spectrometer on Board Hinode
Brosius, Jeffrey W.
The entire profile of the Fe XXIII line at 263.8 Å, formed at temperature ≈14 MK, was blueshifted by an upward velocity -122 ± 33 km s-1 when it was first detected by the Extreme-ultraviolet Imaging Spectrometer operating in rapid cadence (11.18 s) stare mode during a C1 solar flare. The entire profile became even more blueshifted over …