Search Publications
Proper Motions of the HH 47 Jet Observed with the Hubble Space Telescope
Hartigan, Patrick; Bally, John; Reipurth, Bo +2 more
We present a proper-motion study of the shock waves within the classic stellar jet HH 47 based on Hubble Space Telescope (HST) Hα and [S II] images of the region taken over two epochs. Individual knots within the jet and in the bow shock/Mach disk working surface of HH 47A move significantly in the 5 yr that separate the images, and the excellent …
The Complex Star Formation History of NGC 1569
Leitherer, Claus; Greggio, L.; Tosi, M. +3 more
We present new results on the star formation history of the dwarf irregular galaxy NGC 1569. The data were obtained with the Hubble Space Telescope NICMOS/NIC2 in the F110W (J) and F160W (H) near-infrared (NIR) filters and interpreted with the synthetic color-magnitude diagram method. The galaxy has experienced complex star formation (SF) activity…
Opening the Treasure Chest: A Newborn Star Cluster Emerges from Its Dust Pillar in Carina
Smith, Nathan; Stassun, Keivan G.; Bally, John
We present detailed observations of the Treasure Chest, a compact nebula at the head of a dust pillar in the southern Carina Nebula. This object is of interest because it is an example of a dense young cluster containing at least one massive star, the formation of which may have been triggered by feedback from the very massive stars in the Carina …
Red Thick Disks of Nearby Galaxies
Mould, Jeremy
Edge-on systems reveal the properties of disk galaxies as a function of height, z, above the plane. Four local edge-on galaxies that are close enough to have been resolved into stars by the Hubble Space Telescope show thick disks composed of a red stellar population that is old and relatively metal rich. Color gradients, Δ(V-I)/Δz, are zero or sli…
The Lens Redshift and Galaxy Environment for HE 0435-1223
Pevunova, O.; Kochanek, C. S.; Morgan, N. D. +1 more
The redshift of the galaxy lensing HE 0435-1223 is 0.4546+/-0.0002, based on observations obtained with the Low Dispersion Survey Spectrograph 2 on the Magellan Consortium's 6.5 m Clay Telescope. Hubble Space Telescope Advanced Camera for Surveys observations of the system also reveal a spiral-rich group of 10 galaxies within 40" of the elliptical…
Space Telescope Imaging Spectrograph Observations of Young Star Clusters in the Antennae Galaxies (NGC 4038/4039)
Gilmore, Diane; Blair, William P.; Leitherer, C. +6 more
Long-slit spectra of several dozen young star clusters have been obtained at three positions in the Antennae galaxies with the Space Telescope Imaging Spectrograph and its 52''×0.2" slit. Based on Hα emission-line measurements, the average cluster-to-cluster velocity dispersion in seven different cluster aggregates (``knots'') is <10…
New Silhouette Disks with Reflection Nebulae and Outflows in the Orion Nebula and M43
Smith, Nathan; Bally, John; Walawender, Josh +1 more
We report the detection of several new circumstellar disks seen in silhouette against background nebular light in the outskirts of the Orion Nebula and the neighboring H II region M43. These were detected as part of our Hα survey of Orion with the Advanced Camera for Surveys on board the Hubble Space Telescope. Several of the disks show bipolar re…
Spectra of High-Redshift Type Ia Supernovae and a Comparison with Their Low-Redshift Counterparts
Wang, L.; Lidman, C.; Nugent, P. E. +33 more
We present spectra for 14 high-redshift (0.17<z<0.83) supernovae, which were discovered by the Supernova Cosmology Project as part of a campaign to measure cosmological parameters. The spectra are used to determine the redshift and classify the supernova type, essential information if the supernovae are to be used for cosmological studies. R…
Chandra X-Ray Imaging of the Interacting Starburst Galaxy System NGC 7714/7715: Tidal Ultraluminous X-Ray Sources, Emergent Wind, and Resolved H II Regions
Struck, Curtis; Smith, Beverly J.; Nowak, Michael A.
We present high spatial resolution X-ray imaging data for the interacting galaxy pair NGC 7714/7715 (Arp 284) from the Chandra X-ray telescope. In addition to the unresolved starburst nucleus, a variable point source with LX~1040 ergs s-1 was detected 1.5" (270 pc) to the northwest of the nucleus, coincident with a…
A Hubble Space Telescope Snapshot Survey of Dynamically Close Galaxy Pairs in the CNOC2 Redshift Survey
Simard, L.; Carlberg, R. G.; Pritchet, C. J. +3 more
We compare the structural properties of two classes of galaxies at intermediate redshift: those in dynamically close galaxy pairs, and those that are isolated. Both samples are selected from the Canadian Network for Observational Cosmology field galaxy redshift survey (CNOC2) and have redshifts in the range 0.1<z<0.6. Hubble Space Telescope …