News Release Archive:

News Release 81 of 828

February 18, 2010 09:00 AM (EST)

News Release Number: STScI-2010-08

Jurassic Space: Ancient Galaxies Come Together After Billions of Years

Technical facts about this news release:

About the Object

Object Name:	Hickson Compact Group 31, HCG 31
Object Description:	Galaxy Group
Position (J2000):	R.A. 05h 01m 38s.75 Dec. -04° 15' 34".10
Constellation:	Eridanus
Distance:	166 million light-years (51 million parsecs)
Dimensions:	This image is 3.2 arcminutes (156,000 light-years or 48,000 parsecs) wide.

About the Data

Data Description:	This image was created from HST data from proposal 10787: J. Charlton (Pennsylvania State University), A. Zabludoff (University of Arizona), M. de Oliveira (University of São Paulo, Brazil), J. Hibbard (AURA/NRAO), S. Zonak (University of Maryland), A. Hornschemeier (NASA/GSFC), P. Hickson (University of British Columbia), J. Mulchaey (Carnegie Institution of Washington), K. Johnson (University of Virginia), A. Maybhate (STScI), R. Chandar (University of Toledo), S. Gallagher (The University of Western Ontario), C. Palma, S. Hunsberger, N. Brandt, and M. Eracleous (Pennsylvania State University), P. Durrell (Youngstown State University), J. English (University of Manitoba), B. Whitmore (STScI), D. Elmegreen (Vassar College), and K. Knierman (Arizona State University). The science team comprises S. Gallagher (The University of Western Ontario), P. Durrell (Youngstown State University), D. Elmegreen (Vassar College), R. Chandar (University of Toledo), J. English (University of Manitoba), J. Charlton, C. Gronwall, and J. Young (Pennsylvania State University), P. Tzanavaris (NASA/GSFC), K. Johnson (University of Virginia/NRAO), M. de Oliveira (University of São Paulo, Brazil), B. Whitmore (STScI), A. Hornschemeier (NASA/GSFC), et al.
Instrument:	ACS/WFC
Exposure Date(s):	August 8, 2006
Exposure Time:	1.1 hours
Filters:	F435W (B), F606W (V), and F814W (I)

About the Release

Credit:

NASA, ESA, S. Gallagher (The University of Western Ontario), and J. English (University of Manitoba)

Release Date:

February 18, 2010

Note:

Spitzer and GALEX data were combined with the Hubble data to create the composite image. The Spitzer data were taken February 22, 2005 (PI: K. Johnson, University of Virginia/NRAO). The GALEX data were taken December 27, 2004 (archival data). A small amount of WFPC2 data (proposal 5900, PI: P. Conti) taken on October 7, 1995, was used to fill in a portion of the ACS/WFC chip gap in this composite image of HCG 31.

Color:

This image is a composite of separate exposures acquired by three separate space telescopes. Exposures in the optical range of the spectrum were acquired with ACS and WFPC2 instruments on the Hubble Space Telescope (HST). The near-ultraviolet light was acquired by the Galaxy Evolution Explorer (GALEX), while near-infrared emission was captured by the IRAC instrument on the Spitzer Space Telescope (SST). Several filters were used to sample these wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are:

Hubble	ACS/F814W (I), WFPC2/F814W (I)	red
	ACS/F606W (V), WFPC2/F555W (V), WFPC2/F675W(R)	yellow-green
	ACS: F435W (B), WFPC2: F439W (B)	blue
Spitzer	IRAC: 8 micron	orange
GALEX	NUV Imaging Channel	purple

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