PEP Fields

The PEP survey includes six among the most widely studied blank fields across the sky, two high-redshift galaxy clusters and ten lensing clusters.

For infrared surveys, galactic foreground is an important driver in field selection in order to minimize cirrus confusion. At the spatial resolution of Herschel, extrapolations of cirrus noise from previous lower resolution data (Kiss et al. 2005, Jeong et al. 2005) compare favourably low to extragalactic source confusion, allowing to survey not only fields with absolutely minimal foreground (e.g. Lockman Hole) but also fields with I(100)~1 MJy/sr (e.g. COSMOS) but excellent multi-wavelength coverage.

Therefore the availability of multi-wavelength data and follow up opportunities are prime selection criteria. To address our science goals we have ensured that our chosen fields are fully covered in several of the following: deep X-ray surveys, UV/optical/mear-infrared/IRAC imaging, HST imaging, Spitzer mid-infrared surveys, (sub)mm surveys and radio mapping.

The z=1 massive clusters and lensing clusters are chosen to be among the best studied of their category, the latter having known high redshift background objects (in particular (sub)mm galaxies and LBGs) for detailed study.


The Lockman Hole, as covered by the PEP survey.

We use the un-chopped scan mapping mode of the PACS photometer AOR which is the default for PACS photometric mapping of large areas. It is also preferable for imaging close to the source confusion limit, since it avoids additional noise induced by negative beams that would be present in chopped data. This is important since PEP data are at and partly deep into the confusion limit at 160 microns. To improve redundancy of the data and facilitate map reconstruction, including possible low spatial frequency components, we define for each field two basic versions of the mapping AOR, which are scanning the field in orthogonal directions. For the larger fields each AOR version is defined in two flavours for each of these directions, starting in opposite corners of the map respectively.

For most of our maps we use scanning in sky coordinates, in order to optimally match the PEP survey to the known coverage of key multi-wavelength data sets. In order to avoid coverage holes due to the PACS inter-matrix gaps mall cross-scan separations have been adopted, ensuring a good coverage for all observing dates.

All PEP fields are covered by SPIRE observations in the coordinated key programme HerMES of SPIRE SAG1, with the exception of the two z~1 clusters in our programme. PEP include confusion-limited SPIRE scan maps of these two targets, covering the full area mapped with PACS.

A list of the PEP fields and main observing parameters is provided hereafter.




Blank fields

Field 100um
image
[2.5°x2.5°]
Center
RA, Dec
Area P.A.of map
on sky [deg]
Total Exp.
[hours]
5 sigma (70)
[mJy]
5 sigma (100)
[mJy]
5 sigma(160)
[mJy]
COSMOS 10:00:28.6
+02:12:21
85'x85' 0.0 213 -- 7.50 16.35
Lockman Hole 10:52:43.0
+57:28:48
24'x24' 0.0 35 -- 6.20 14.60
E-CDFS 03:32:25.0
-27:48:50
30'x30' 0.0 35 -- 6.25 13.05
Groth Strip 14:19:17.4
+52:49:34
67'x10' 40 35 -- 5.80 12.30
GOODS-S* 03:32:30.4
-27:48:17
10'x15' -10 113+113 1.65 0.90 2.15
GOODS-N* 12:36:54.9
+62:14:19
10'x15' 40 30 -- 1.60 3.50

(*) the 100 and 160 micron sensitivities of the GOODS fields refer to the combined reduction of PEP and GOODS-Herschel data, as described by Magnelli et al. (2013).

z~1 clusters

Field Center
RA, Dec
Area P.A.of map
on sky [deg]
Total Exp.
[hours]
5 sigma (70)
[mJy]
5 sigma (100)
[mJy]
5 sigma(160)
[mJy]
MS 1054 10:57:00.2
-03:37:27
5'x10' 0.0 5 -- 5.50 12.85
MS 1054 (SPIRE) 10:57:00.2
-03:37:27
5'x10' 0.0 0.84 -- -- --
RXJ 0152.7 01:52:41.0
-13:57:45
5'x10' 45 5 -- 5.70 12.75
RXJ 0152.7 (SPIRE) 01:52:41.0
-13:57:45
5'x10' 45 0.84 -- -- --



Lensing clusters

Field Center
RA, Dec
Area P.A.of map
on sky [deg]
Total Exp.
[hours]
5 sigma (70)
[mJy]
5 sigma (100)
[mJy]
5 sigma(160)
[mJy]
Abell 1689 13:11:30.3
-01:20:24
4'x4' 45 13 -- 2.85 6.90
Abell 1835 14:01:02.0
+02:52:44
4'x4' 45 5 -- 4.45 10.50
Abell 2218 16:35:53.0
+66:12:22
4'x4' 45 13 -- 3.55 9.15
Abell 2219 16:40:20.0
+46:42:43
4'x4' 45 5 -- 4.15 9.90
Abell 2390 21:53:37.0
+17:41:44
4'x4' 45 5 -- 4.55 12.70
Abell 370 02:39:53.0
-01:34:43
4'x4' 45 5 -- 4.50 11.40
CI 0024+16 00:26:36.0
+17:09:45
4'x4' 45 6.4 -- 4.85 11.35
MS 0451.6-0305 04:54:12.0
-03:01:00
4'x4' 45 5 -- 4.30 11.20
MS 1358+62 13:59:54.3
+62:30:36
4'x4' 45 5 -- 4.30 10.60
RXJ 13475 13:47:30.5
-11:45:09
4'x4' 45 5 -- 4.45 10.85
 
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