Open AccessA faint red stellar halo around an edge‐on disc galaxy in the Hubble Ultra Deep Field
Author(s) -
Zibetti Stefano,
Ferguson Annette M. N.
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.08106.x
Subject(s) - physics , astrophysics , halo , hubble ultra deep field , galaxy , surface brightness , astronomy , redshift , hubble deep field , surface brightness fluctuation , disc galaxy , elliptical galaxy
We analyse the detailed structure of a highly‐inclined ( i ≳ 80°) disc galaxy that lies within the Hubble Ultra Deep Field (UDF). The unprecedented depth of the UDF data allow disc and extraplanar emission to be traced reliably to surface brightness levels of μ V , i , z ∼ 29–30 mag arcsec −2 (corresponding to rest‐frame equivalents of μ g , r , i ∼ 28–29 mag arcsec −2 ) in this redshift z = 0.32 system. We detect excess emission above the disc, which is characterized by a moderately flattened ( b / a ∼ 0.6) power law ( I ∝ R −2.6 ) . The structure and colour of this component are very similar to the stellar halo detected in an SDSS stacking analysis of local disc galaxies and lend support to the idea that we have detected a stellar halo in this distant system. Although the peculiar colours of the halo are difficult to understand in terms of normal stellar populations, the consistency found between the UDF and SDSS analyses suggests that they cannot be easily discounted.