News Release Archive:

News Release 9 of 56

January 11, 2012 10:30 AM (EST)

News Release Number: STScI-2012-03

Rare Ultra-blue Stars Found in Neighboring Galaxy's Hub

Technical facts about this news release:

About the Object

Object Description:	PHAT Treasury Survey Region of M31
Position (J2000):	R.A. 00h 42m 44s Dec. +41° 16' 9"
Constellation:	Andromeda
Distance:	About 2.5 million light-years (0.8 megaparsecs)

About the Data

Data Description:	The Panchromatic Hubble Andromeda Treasury (PHAT) survey of M31 is an ongoing HST Treasury proposal. These images were created from Hubble data from proposal 12058 (PI: J. Dalcanton, University of Washington, Seattle).
Instrument:	WFC3/UVIS, WFC3/IR, and ACS/WFC
Exposure Date(s):	Data used in these images were taken in 2010 and 2011.
Filters:	WFC3/UVIS: F275W (UV) and F336W (U) ACS/WFC: F475W (g) and F814W (I) WFC3/IR: F160W (H)

About the Release

Credit:

NASA, ESA, and B. Williams and J. Dalcanton (University of Washington, Seattle)

Release Date:

January 11, 2012

Color:

This image is a composite of separate exposures acquired by the WFC3 and ACS instruments on HST. Several filters were used to sample broad 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:

Wide M31 Image (at top)
WFC3/UVIS: F336W (U)	blue
ACS/WFC: F475W (g)	cyan
ACS/WFC: F814W (I)	yellow
WFC3/IR: F160W (H)	red

Detail M31 Image (at bottom)
WFC3/UVIS: F275W (UV)	light purple
WFC3/UVIS: F336W (U)	blue
ACS/WFC: F475W (g)	green
ACS/WFC: F814W (I)	dark red

Orientation/Scale: