Search Publications
The Unusual Infrared Object HDF-N J123656.3+621322
Papovich, Casey; Dickinson, Mark; Ferguson, Henry C. +11 more
We describe an object in the Hubble Deep Field North with very unusual near-infrared properties. It is readily visible in Hubble Space Telescope NICMOS images at 1.6 µm and from the ground at 2.2 µm, but it is undetected (with S/N<~2) in very deep WFPC2 and NICMOS data from 0.3 to 1.1 µm. The fν flux density drops b…
On the Globular Cluster Initial Mass Function below 1 Msolar
Paresce, Francesco; De Marchi, Guido
Accurate luminosity functions (LFs) for a dozen globular clusters have now been measured at or just beyond their half-light radius using HST. They span almost the entire cluster main sequence (MS) below 0.75 Msolar. All these clusters exhibit LFs that rise continuously from an absolute I magnitude MI~=6 to a peak at MI
Magnetic Geometry and Dynamics of the Fast Coronal Mass Ejection of 1997 September 9
Burkepile, J. T.; Chen, J.; Howard, R. A. +6 more
A coronal mass ejection (CME) was observed on 1997 September 9 by the Mauna Loa Solar Observatory Mark III K-coronameter (MK3) and by the LASCO C2/C3 and EIT instruments on board the SOHO spacecraft. Magnetograms and EIT images obtained on days leading up to the eruption show a neutral line that appears to correspond to the site of the eruption. T…
Molecular Gas, Dust, and Star Formation in the Barred Spiral NGC 5383
Sheth, Kartik; Vogel, Stuart N.; Regan, Michael W. +1 more
We have mapped the barred spiral NGC 5383 using the Berkeley-Illinois-Maryland Association millimeter-wave array for observations of CO (J=1-0), the Palomar 1.5 m telescope for Hα and optical broadband, and the Kitt Peak 1.3 m telescope for near-IR broadband. We compare the observed central gas and dust morphology to the predictions of recent hydr…
Deep 10 and 18 Micron Imaging of the HR 4796A Circumstellar Disk: Transient Dust Particles and Tentative Evidence for a Brightness Asymmetry
Ghez, A. M.; Telesco, C. M.; Prato, L. +9 more
We present new 10.8 and 18.2 µm images of HR 4796A, a young A0 V star that was recently discovered to have a spectacular, nearly edge-on, circumstellar disk prominent at ~20 µm (Jayawardhana and coworkers; Koerner and coworkers). These new images, obtained with OSCIR (the University of Florida Observatory Spectrometer/Camera for the In…
HST/STIS Ultraviolet Imaging of Polar Aurora on Ganymede
Wolven, Brian C.; Feldman, Paul D.; Strobel, Darrell F. +3 more
We report new observations of the spectrum of Ganymede in the spectral range 1160-1720 Å made with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST) on 1998 October 30. The observations were undertaken to locate the regions of the atomic oxygen emissions at 1304 and 1356 Å, previously observed with the Goddard Hig…
From Stars to Superplanets: The Low-Mass Initial Mass Function in the Young Cluster IC 348
Najita, Joan R.; Tiede, Glenn P.; Carr, John S.
We investigate the low-mass population of the young cluster IC 348 down to the deuterium-burning limit, a fiducial boundary between brown dwarf and planetary mass objects, using a new and innovative method for the spectral classification of late-type objects. Using photometric indices, constructed from HST/NICMOS narrowband imaging, that measure t…
Resolving Gamma-Ray Burst 000301C with a Gravitational Microlens
Loeb, Abraham; Garnavich, Peter M.; Stanek, K. Z.
The afterglow of the gamma-ray burst (GRB) 000301C exhibited achromatic, short-timescale variability that is difficult to reconcile with the standard relativistic shock model. We interpret the observed light curves as a microlensing event superposed on power-law flux decays typical of afterglows. In general, a relativistic GRB shock appears on the…
The X-Ray Remnant of SN 1987A
Petre, Robert; Chevalier, Roger A.; Garmire, Gordon P. +6 more
We present high-resolution Chandra observations of the remnant of SN 1987A in the Large Magellanic Cloud. The high angular resolution of the Chandra X-Ray Observatory permits us to resolve the X-ray remnant. We find that the remnant is shell-like in morphology, with X-ray peaks associated with some of the optical hot spots seen in Hubble Space Tel…
Three-dimensional Stereoscopic Analysis of Solar Active Region Loops. II. SOHO/EIT Observations at Temperatures of 1.5-2.5 MK
Klimchuk, J. A.; Alexander, David; Aschwanden, Markus J. +4 more
In this paper we study the three-dimensional structure of hot (Te~1.5-2.5 MK) loops in solar active region NOAA 7986, observed on 1996 August 30 with the Extreme-ultraviolet Imaging Telescope (EIT) on board the Solar and Heliospheric Observatory (SOHO). This complements a first study (Paper I) on cooler (Te~1.0-1.5 MK) loops …