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We present a method of mapping dust column density in dark clouds by using near-infrared scattered light. Our observations of the Lupus 3 dark cloud indicate that there is a well defined relation between (1) the H-Ks color of an individual…

A high latitude HI 21 cm-line absorption survey toward extragalactic sources was recently completed using the Giant Meterwave Radio Telescope (GMRT). A total of 104 sources with mod(b) > 15 deg. and with a 21 cm flux density greater than 1…

Astrophysics · Physics 2007-05-23 K. S. Dwarakanath

We investigate the far-infrared properties of galaxies selected via deep, narrow-band imaging of the H$\alpha$ emission line in four redshift slices from $z=0.40$--$2.23$ over $\sim 1$deg$^2$ as part of the High-redshift Emission Line…

Astrophysics of Galaxies · Physics 2017-04-05 Alasdair Thomson , James Simpson , Ian Smail , Mark Swinbank , Philip Best , David Sobral , James Geach , Edo Ibar , Helen Johnson

Models that reproduce the observed high-velocity clouds (HVCs) also predict clouds at lower radial velocities that may easily be confused with Galactic disk (|z| < 1 kpc) gas. We describe the first search for these low-velocity halo clouds…

Astrophysics · Physics 2011-02-11 J. E. G. Peek , Carl Heiles , M. E. Putman , Kevin A. Douglas

We map the dust distribution in the central 180" (~680 pc) region of the M31 bulge, based on HST/WFC3 and ACS observations in ten bands from near-ultraviolet (2700 A) to near-infrared (1.5 micron). This large wavelength coverage gives us…

Astrophysics of Galaxies · Physics 2016-04-20 Hui Dong , Zhiyuan Li , Q. D. Wang , Tod R. Lauer , Knut A. G. Olsen , Abhijit Saha , Julianne J. Dalcanton , Brent A. Groves

Scattering and absorption of light by a homogeneous distribution of intergalactic large dust grains has been proposed as an alternative, non-cosmological explanation for the faintness of Type Ia supernovae at $z\s im 0.5$. We investigate…

Astrophysics · Physics 2009-11-07 Ariel Goobar , Lars Bergstrom , Edvard Mortsell

We report results of a near--infrared imaging survey of L977, a dark cloud in Cygnus seen in projection against the plane of the Milky Way. We use measurements of the near--infrared color excess and positions of the 1628 brightest stars in…

Astrophysics · Physics 2009-10-30 J. Alves , C. Lada , E. Lada , S. Kenyon , R. Phelps

The chromospheric H-alpha spectral line is a strong line in the spectrum of the Sun and other stars. In the stellar regime, this spectral line is already used as a powerful tracer of stellar activity. For the Sun, other tracers (i.e, CaII…

Solar and Stellar Astrophysics · Physics 2022-05-18 A. Diercke , C. Kuckein , P. W. Cauley , K. Poppenhäger , J. D. Alvarado-Gómez , E. Dineva , C. Denker

It has been suggested that high velocity clouds may be distributed throughout the Local Group and are therefore not in general associated with the Milky Way galaxy. With the aim of testing this hypothesis, we have made observations in the…

Astrophysics · Physics 2009-11-07 S. L. Tufte , J. D. Wilson , G. J. Madsen , L. M. Haffner , R. J. Reynolds

Recently completed H-Alpha surveys of large portions of the sky can be used to create maps of the free-free intensity distribution at high Galactic latitude that are independent of the spectral fits to the CMB data. This provides an…

Astrophysics · Physics 2007-05-23 R. J. Reynolds , L. M. Haffner

We have carried out a sensitive high-latitude (|b| > 15deg.) HI 21cm-line absorption survey towards 102 sources using the GMRT. With a 3-sigma detection limit in optical depth of ~0.01, this is the most sensitive HI absorption survey. We…

Astrophysics · Physics 2009-11-10 Rekhesh Mohan , K. S. Dwarakanath , G. Srinivasan

We present results from a near-infrared narrow-band survey of emission-line galaxies at z=2.23, using the Wide Field Camera on the United Kingdom Infrared Telescope. The H2S1 narrow-band filter (lambda_c=2.121um) we employ selects the…

Astrophysics · Physics 2009-11-13 J. E. Geach , Ian Smail , P. N. Best , J. Kurk , M. Casali , R. J. Ivison , K. Coppin

To investigate the fundamental principles of H2 formation in a giant molecular cloud (GMC), we derive the HI and H2 surface density (Sigma_HI and Sigma_H2) images of the Perseus molecular cloud on sub-pc scales (~0.4 pc). We use the…

We perform Lyman-alpha radiative transfer calculations for reproducing Lyman-alpha properties of star-forming galaxies at high redshifts. We model a galaxy as a halo in which the density distributions of Lyman-alpha sources and H I plus…

Astrophysics of Galaxies · Physics 2020-09-30 Hyunmi Song , Kwang-Il Seon , Ho Seong Hwang

We investigate the nature of the mid-IR excess for 31 intermediate-mass stars that exhibit an 8 micron excess in either the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire or the Mid-Course Space Experiment using high resolution…

Astrophysics · Physics 2009-11-13 B. Uzpen , H. A. Kobulnicky , D. R. Semler , T. Bensby , C. Thom

Context. G29.96-0.02 is a high-mass star-forming cloud observed at 70, 160, 250, 350, and 500 microns as part of the Herschel survey of the Galactic Plane during the Science Demonstration Phase. Aims. We wish to conduct a far-infrared study…

We investigate the effects of dust on Large Magellanic Cloud (LMC) HII region spectral energy distributions using arcminute-resolution far-ultraviolet (FUV), H-alpha, far-infrared (FIR), and radio images. Widely-used indicators of the…

Astrophysics · Physics 2009-11-07 Eric F. Bell , Karl D. Gordon , Robert C. Kennicutt , Dennis Zaritsky

We derive H{\alpha} fluxes for a large spectroscopic and photometric-redshift-selected sample of sources over GOODS-North and South in the redshift range z = 3.8-5.0 with deep HST, Spitzer/IRAC, and ground-based observations. The H{\alpha}…

Astrophysics of Galaxies · Physics 2016-12-28 Renske Smit , Rychard J. Bouwens , Ivo Labbé , Marijn Franx , Stephen M. Wilkins , Pascal A. Oesch

We present new narrow-band H alpha imaging from the Hubble Space Telescope of two redshift 0.91 galaxies that have been lensed by foreground galaxy cluster Abell 2390. These data probe spatial scales as small as 0.3 kpc, providing a…

Astrophysics of Galaxies · Physics 2015-06-23 Alice Olmstead , Jane R. Rigby , Mark Swinbank , Sylvain Veilleux

We have detected over 400 HI clouds in the lower halo of the Galaxy within the pilot region of the Galactic All-Sky Survey (GASS), a region of the fourth quadrant that spans 18 degrees in longitude, 40 degrees in latitude and is centered on…