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The Star Formation History of Galaxies Measured from Individual Pixels. I. The Hubble Deep Field North
Hopkins, Andrew M.; Csabai, István; Connolly, Andrew J. +6 more
We analyze the photometric information contained in individual pixels of galaxies in the Hubble Deep Field North (HDF-N) using a new technique, pixel-z, that combines predictions of evolutionary synthesis models with photometric redshift template fitting. Each spectral energy distribution template is a result of modeling of the detailed physical p…
Optical and Near-Infrared Spectroscopy of a High-Redshift Hard X-Ray-emitting Spiral Galaxy
Graham, James R.; Eckart, Megan E.; Spinrad, Hyron +4 more
We present optical and near-infrared Keck spectroscopy of CXOHDFN J123635.6+621424 (HDFX 28), a hard X-ray source at a redshift of z=2.011 in the flanking fields of the Hubble Deep Field North (HDF-N). HDFX 28 is a red source (R-Ks=4.74) with extended steep-spectrum (α8.41.4 GHz>0.87 GHz) microjansky radio emiss…
Photometric Studies of the Triple Star ER Orionis
Kim, Ho-Il; Lee, Jae Woo; Kim, Chun-Hwey +2 more
A total of 1637 BVR CCD observations of the overcontact binary ER Ori are used as the basis for new light curves, including the first red one. From these measurements, new timings of minimum light have been calculated. The complex period variation can be sorted into a linear period improvement, a secular period increase of considerable magnitude, …
Multiwavelength Insights into Mixed-Morphology Binary Galaxies. I. ISOCAM, ISOPHOT, and Hα Imaging
Rampazzo, Roberto; Xu, Cong; Gao, Yu +3 more
We present Hα and ISO mid- and far-IR observations for a sample of mixed-morphology galaxy pairs that reveal both the stellar and nonstellar signatures of the interaction process. A mixed-morphology pair is perhaps the simplest form of galaxy-galaxy interaction because it is expected to involve only a single rapidly rotating gas-rich component pai…
Infrared Space Observatory and Ground-Based Infrared Observations of the Classical Nova V723 Cassiopeiae
Hayward, T. L.; Gehrz, R. D.; Eyres, S. P. S. +13 more
We present observations of the classical nova V723 Cassiopeiae (Nova Cas 1995), obtained both with the Infrared Space Observatory (ISO) and from the ground. The infrared spectrum was dominated in the first year by H and He recombination lines, and at later times by coronal lines. The H recombination lines imply a reddening of E(B-V)=0.78, an elect…
Star Formation and Asymmetry in the Spiral Arms of M51: Variable Star Formation Caused by More than One Spiral Density Wave
Gutermuth, Robert; Quillen, A. C.; Henry, Alaina L.
In the inner 3 kpc of M51, we find that logarithmic spirals provide good fits to the peak intensities in molecular gas observed by the Berkeley-Illinois-Maryland Association array in the CO (J=1-0) emission line along the spiral arms. However, we measure significant asymmetries between the location and density of the arms observed on one side of t…
Time Series Photometry of Variable Stars in the Globular Cluster NGC 6397
Thompson, I. B.; Kaluzny, J.
Time series BVI photometry is presented for 16 short-period variables located in the central region of the globular cluster NGC 6397. The sample includes nine newly detected variables. The light curve of cataclysmic variable CV6 shows variability with a period of 0.2356 days. We confirm an earlier reported period of 0.472 days for cataclysmic vari…
Active Star Formation in the N11B Nebula in the Large Magellanic Cloud: A Sequential Star Formation Scenario Confirmed
Barbá, Rodolfo H.; Rubio, Mónica; Roth, Miguel R. +1 more
The second largest H II region in the Large Magellanic Cloud, N11B has been surveyed in the near-IR. We present JHKs images of the N11B nebula. These images are combined with CO (1-->0) emission-line data and with archival New Technology Telescope and Hubble Space Telescope WFPC2 optical images to address the star formation activity …
The Ringed Spiral Galaxy NGC 4622. I. Photometry, Kinematics, and the Case for Two Strong Leading Outer Spiral Arms
Byrd, Gene G.; Freeman, Tarsh; Buta, Ronald J.
The intriguing nearly face-on southern ringed spiral galaxy NGC 4622, the first galaxy definitively shown to have leading spiral structure, is revisited in this paper with new images from the Hubble Space Telescope's (HST) WFPC2, together with ground-based optical and near-IR imaging, and a Fabry-Perot Hα velocity field. The data provide new infor…
Stellar Populations in NGC 4038/39 (the Antennae): Exploring a Galaxy Merger Pixel by Pixel
Pogge, Richard W.; Frogel, Jay A.; Kassin, Susan A. +2 more
We present deep, photometrically calibrated BVRJHK images of the nearby interacting galaxy pair NGC 4038/39 (the Antennae). Color maps of the images are derived, and those using the B, V, and K bands are analyzed with techniques developed for examining the colors of stars. From these data we derive pixel-by-pixel maps of the distributions of stell…