TY - JOUR
T1 - Submillimeter number counts from statistical analysis of blast maps
AU - Patanchon, Guillaume
AU - Ade, Peter A.R.
AU - Bock, James J.
AU - Chapin, Edward L.
AU - Devlin, Mark J.
AU - Dicker, Simon R.
AU - Griffin, Matthew
AU - Gundersen, Joshua O.
AU - Halpern, Mark
AU - Hargrave, Peter C.
AU - Hughes, David H.
AU - Klein, Jeff
AU - Marsden, Gaelen
AU - Mauskopf, Philip
AU - Moncelsi, Lorenzo
AU - Netterfield, Calvin B.
AU - Olmi, Luca
AU - Pascale, Enzo
AU - Rex, Marie
AU - Scott, Douglas
AU - Semisch, Christopher
AU - Thomas, Nicholas
AU - Truch, Matthew D.P.
AU - Tucker, Carole
AU - Tucker, Gregory S.
AU - Viero, Marco P.
AU - Wiebe, Donald V.
PY - 2009
Y1 - 2009
N2 - We describe the application of a statistical method to estimate submillimeter galaxy number counts from confusion-limited observations by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST). Our method is based on a maximum likelihood fit to the pixel histogram, sometimes called "P(D)," an approach which has been used before to probe faint counts, the difference being that here we advocate its use even for sources with relatively high signal-to-noise ratios. This method has an advantage over standard techniques of source extraction in providing an unbiased estimate of the counts from the bright end down to flux densities well below the confusion limit. We specifically analyze BLAST observations of a roughly 10 deg 2 map centered on the Great Observatories Origins Deep Survey South field. We provide estimates of number counts at the three BLAST wavelengths 250, 350, and 500μm; instead of counting sources in flux bins we estimate the counts at several flux density nodes connected with power laws. We observe a generally very steep slope for the counts of about -3.7 at 250 μm, and -4.5 at 350 and 500 μm, over the range 0.02-0.5 Jy, breaking to a shallower slope below about 0.015 Jy at all three wavelengths. We also describe how to estimate the uncertainties and correlations in this method so that the results can be used for model-fitting. This method should be well suited for analysis of data from the Herschel satellite.
AB - We describe the application of a statistical method to estimate submillimeter galaxy number counts from confusion-limited observations by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST). Our method is based on a maximum likelihood fit to the pixel histogram, sometimes called "P(D)," an approach which has been used before to probe faint counts, the difference being that here we advocate its use even for sources with relatively high signal-to-noise ratios. This method has an advantage over standard techniques of source extraction in providing an unbiased estimate of the counts from the bright end down to flux densities well below the confusion limit. We specifically analyze BLAST observations of a roughly 10 deg 2 map centered on the Great Observatories Origins Deep Survey South field. We provide estimates of number counts at the three BLAST wavelengths 250, 350, and 500μm; instead of counting sources in flux bins we estimate the counts at several flux density nodes connected with power laws. We observe a generally very steep slope for the counts of about -3.7 at 250 μm, and -4.5 at 350 and 500 μm, over the range 0.02-0.5 Jy, breaking to a shallower slope below about 0.015 Jy at all three wavelengths. We also describe how to estimate the uncertainties and correlations in this method so that the results can be used for model-fitting. This method should be well suited for analysis of data from the Herschel satellite.
KW - Cosmology: observations
KW - Galaxies: statistics
KW - Methods: data analysis
KW - Submillimeter
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U2 - 10.1088/0004-637X/707/2/1750
DO - 10.1088/0004-637X/707/2/1750
M3 - Article
AN - SCOPUS:72849147190
SN - 0004-637X
VL - 707
SP - 1750
EP - 1765
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
ER -