Search Publications
Precision Limits to Emission-Line Profile Measuring Experiments
Ireland, J.
Spectra, such as astrophysical spectra, can provide detailed diagnostics on the state of their emitting volume. Emission-line diagnostics are found by assuming a model for the spectral emission line and then fitting the model to the data. It is shown for Poisson noisy emission-line data, via the application of Cramér-Rao lower bounds, that there a…
The Infrared-dominated Jet of 3C 401
Axon, David J.; Chiaberge, Marco; Capetti, Alessandro +6 more
We present a Hubble Space Telescope image of the FR II radio galaxy 3C 401, obtained at 1.6 µm with NICMOS, in which we identify the infrared counterpart of the brightest region of the radio jet. The jet has a complex radio structure and brightens where bending occurs, most likely as a result of relativistic beaming. We analyze archival data…
Possible Optical Detection of the Anomalous X-Ray Pulsar CXOU J010043.1-721134
Durant, Martin; van Kerkwijk, Marten H.
Archival Hubble Space Telescope Wide Field Planetary Camera 2 observations of the Small Magellanic Cloud have serendipitously revealed a possible counterpart to the anomalous X-ray pulsar CXOU J010043.1-721134. The candidate is faint, but its location and strange colors make it an interesting object. We estimate that the probability of such a dete…
Coronal Element Comparison Observed by SOHO SUMER in the Quiet Southeast and Northwest Limb Regions at 1.04 Rsolar above the Solar Disk
Landi, E.; Feldman, U.; Widing, K. G.
The composition in an isothermal region at 1.04 Rsolar above a diffuse, quiet coronal region on the northwest limb is studied and compared with a similar region above the southeast limb analyzed by Warren in 1999. Elemental abundances relative to H in the corona are measured and normalized to the abundance ratios in the photosphere. The…
Detectability of Gamma-Ray Burst Iron Lines by Swift, Chandra, and XMM-Newton
Kallman, T. R.; Mészáros, P.; Gou, L. J.
The rapid acquisition of positions by the upcoming Swift satellite will allow monitoring for X-ray lines in gamma-ray burst (GRB) afterglows at much earlier epochs than was previously feasible. We calculate the possible significance levels of iron-line detections as a function of source redshift and observing time after the trigger for the Swift X…
An X-Ray Transient and Optical Counterpart in the M31 Bulge
Williams, Benjamin F.; McClintock, Jeffrey E.; Kong, Albert K. H. +3 more
We have obtained snapshot images of a transient X-ray source in M31 from Chandra ACIS-I and the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The Chandra position of the X-ray nova was R.A.=00h42m56.038s+/-0.08", decl.=+41deg12'18.50"+/-0.07". The transient was active for at least 6 mon…
On the Discovery of the First Galaxy Selected at 350 Microns
Eisenhardt, Peter R.; Clements, David L.; Gonzalez, Anthony H. +17 more
We report the detection of a 3.6 σ source selected at 350 µm in the Boötes Deep Field. The source, the first short-wavelength submillimeter-selected galaxy (SSG 1), was discovered as part of a blank-field extragalactic survey using the 350 µm-optimized Submillimeter High Angular Resolution Camera (SHARC II) at the Caltech Submillimeter…
A Study of Far-Ultraviolet Extinction in the Upper Scorpius Cloud Using the SPINR Sounding Rocket Experiment
Chakrabarti, S.; Lewis, N. K.; Cook, T. A.
In this study, six new interstellar extinction curves in the far-ultraviolet are presented using data from a sounding rocket experiment. The sounding rocket data were combined with IUE data for six lines of sight in the Upper Scorpius group to cover the wavelength range of 912-3030 Å. The extinction curves were produced using the pair comparison m…
A High-Resolution Mosaic of Molecular Gas in Stephan's Quintet
Petitpas, Glen R.; Taylor, Christopher L.
We present high-resolution 12CO J=1-0 observations of the molecular gas in the Hickson compact group Stephan's Quintet (HCG 92). Our observations consist of multiple pointings and mosaics covering all the regions where CO and star formation have been detected. Within the 100" field of view centered on the easternmost tidal tail, we dete…
A Potential Supernova Remnant-X-Ray Binary Association in M31
Williams, Benjamin F.; Kong, Albert K. H.; Kolb, U. +3 more
The well-studied X-ray/optical/radio supernova remnant (SNR) DDB 1-15 (CXOM31 J004327.8+411829; r3-63) in M31 has been investigated with archival XMM-Newton and Chandra observations. The timing data from XMM-Newton reveal a power density spectrum (PDS) characteristic of accreting compact objects in X-ray binaries (XRBs). The PDS shows features typ…