Supernovae Discovered with ACS between 2-4 April 2004

R. Gibbons (LBL) on behalf of the Supernova Cosmology Project (cf. IAUC
8119, plus N. Kashikawa, M. Kowalski, N. Kuzentsova, T. Morokuma),
and A. Riess (STScI) on behalf of L. Strolger, H. Ferguson, T. Dahlen
(STScI), and P. Challis (CfA), report the discovery of 11 supernovae
found with the Advanced Camera for Surveys (ACS) on the Hubble Space
Telescope during the period 02-04 April 2004.  Subtractions of the one
year old GOODS HDF-N survey data from new F850LP (z') and F775W (i')
imaging revealed supernovae at signal-to-noise ratios greater than
6 within 0''.2  apertures, but typically well above 15.  The search
imaging consisted of sums of four 400s z' exposures and one 400s i'
exposure.  Resulting limiting Vega magnitudes in the search data were
z'=26.2 and i'=26.5.  The reference images were sums of all the GOODS
data taken between 21-Nov-2002 and 25-May-2003 and reached limiting
magnitudes of z'=27.4 and i'=28.4.  None of the objects reported here
were present in the year old references nor was there evidence of motion
over the course of our search observations.  The brightness of each
candidate was consistent in the individual z' images that went into the
z' sums.  B. Mobasher provided host galaxy photometric redshifts which
were estimated from GOODS survey data.  These ranged between z~0.5-2.0.
Our final list of supernovae includes only those events with magnitudes
and colors which were consistent with the photometric redshifts.  At the
positions of all the candidates we found, none of the host galaxies
showed evidence of variability over the course of the GOODS survey,
although we did exclude from this list one candidate which was on the
core of its host.  Supernova are sorted by right ascension.

SN         2004 UT        R.A. (2000.0) Decl.      z'     i'     Offset 
acs04-193  Apr. 02.74   12 36 19.86  +62 13 48.0   25.1   25.5   0''.15 S 
acs04-177       02.08   12 36 20.90  +62 10 19.6   25.4   26.3   0''.70 SW
acs04-176       02.08   12 36 25.93  +62 09 37.4   23.7   **     0''.67 S 
acs04-194       02.74   12 36 27.07  +62 15 09.6   24.4   25.1   0''.24 SE
acs04-185       02.08   12 36 29.44  +62 11 41.9   24.4   24.3   0''.06 NW
acs04-186       04.71   12 36 46.07  +62 16 25.7   25.8   **     0''.17 SE
acs04-181       04.71   12 36 49.36  +62 16 04.8   24.9   25.7   0''.03 SE
acs04-196       03.40   12 37 06.73  +62 21 17.8   25.4   25.7   0''.05 SW
acs04-076       03.40   12 37 09.44  +62 22 15.6   25.1   26.5   0''.80 NE
acs04-197       03.54   12 37 21.32  +62 09 35.2   25.7  >26.5   0''.12 NW
acs04-195       03.34   12 38 03.58  +62 17 11.9   24.7   25.2   0''.98 N 

** i' band data not available

z' and i' are given in Vega magnitudes.  Offsets are supernovae position
with respect to host.