II/363 The band-merged unWISE Catalog (Schlafly+, 2019)
The unWISE Catalog: two billion infrared sources from five years of WISE
imaging.
Schlafly E.F., Meisner A.M., Green G.M.
<Astrophys. J. Suppl. Ser., 240, 30 (2019)>
=2019ApJS..240...30S 2019ApJS..240...30S
=2020yCat.2363....0S 2020yCat.2363....0S
ADC_Keywords: Infrared sources ; Photometry, infrared ; Surveys
Mission_Name: WISE
Keywords: catalogs ; infrared: general ; surveys ; techniques: photometric
Abstract:
We present the unWISE Catalog, containing the positions and fluxes of
roughly 2 billion objects observed by the Wide-field Infrared Survey
Explorer (WISE) over the full sky. The unWISE Catalog has two
advantages over the existing WISE catalog (AllWISE): first, it is
based on significantly deeper imaging, and second, it features
improved modeling of crowded regions. The deeper imaging used in the
unWISE Catalog comes from the coaddition of all publicly available
3-5um WISE imaging, including that from the ongoing
NEOWISE-reactivation mission, thereby increasing the total exposure
time by a factor of 5 relative to AllWISE. At these depths, even at
high Galactic latitudes, many sources are blended with their
neighbors; accordingly, the unWISE analysis simultaneously fits
thousands of sources to obtain accurate photometry. Our new catalog
detects sources roughly 0.7mag fainter than the AllWISE catalog at
5σ, and more accurately models millions of faint sources in the
Galactic plane, enabling a wealth of Galactic and extragalactic
science. In particular, relative to AllWISE, unWISE doubles the number
of galaxies detected between redshifts 0 and 1 and triples the number
between redshifts 1 and 2, cataloging more than half a billion
galaxies over the whole sky.
Description:
The unWISE Catalog analyzes the unWISE coadds of the WISE images to
detect two billion sources over the entire sky at 3.4 and 4.6microns.
The WISE point spread function has a full-width at half-maximum of
about 6", which coupled with the large number of sources means that
many sources significantly overlap with others. To accurately model
the photometry of these blended sources, the crowdsource (available on
GitHub) analysis pipeline was used to simultaneously determine the
positions and fluxes of all sources in the unWISE coadds. The greater
depth of the unWISE coadds relative to those from the first year of
the survey, combined with the crowdsource crowded-field modeling,
allow the unWISE catalog to detect roughly three times as many sources
as were detected in the AllWISE catalog.
Acknowledging WISE in publications:
Please include the following in any published material that makes use
of the WISE data products:
"This publication makes use of data products from the Wide-field
Infrared Survey Explorer, which is a joint project of the University of
California, Los Angeles, and the Jet Propulsion Laboratory/California
Institute of Technology, funded by the National Aeronautics and Space
Administration."
Please cite one or more of:
Lang, D., 2014, "unWISE: unblurred coadds of the WISE imaging"
Astronomical Journal, 147, 108.
Meisner, A.M., Lang, D., and Schlegel, D.J., 2017, "Full-depth Coadds
of the WISE and First-year NEOWISE-Reactivation Images"
Astronomical Journal, 153, 38.
Meisner, A.M., Lang, D., and Schlegel, D.J., 2017, "Deep Full-sky
Coadds from Three Years of WISE and NEOWISE Observations"
Astronomical Journal, 154, 161.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
unwise.sam 563 1000 Sample of the band-merged unWISE catalog
(among 2,214,734,224 sources)
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See also:
VII/237 : HYPERLEDA. I. Catalog of galaxies (Paturel+, 2003)
II/311 : The WISE All-Sky data Release (Cutri+ 2012)
II/328 : The AllWISE data Release (Cutri+ 2013)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
J/ApJS/197/19 : First brown dwarfs discovered by WISE (Kirkpatrick+, 2011)
J/ApJ/757/83 : The Blanco Cosmology Survey (BCS) (Desai+, 2012)
J/ApJ/792/30 : NEOWISE magnitudes for near-Earth objects (Mainzer+, 2014)
J/AJ/152/63 : NEOWISE reactivation mission: 2nd yr data (Nugent+, 2016)
J/ApJS/224/24 : The COSMOS2015 catalog (Laigle+, 2016)
J/ApJ/819/24 : z>4.5 QSOs with SDSS and WISE. I. Opt. spectra (Wang+, 2016)
http://catalog.unwise.me/ : The unWISE Catalog home page
http://www.jpl.nasa.gov/missions/wide-field-infrared-survey-explorer-wise/ :
The WISE home page
Byte-by-byte Description of file: unwise.sam
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Bytes Format Units Label Explanations
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1- 16 A16 --- objID Unique object identifier (unwise_objid)
18- 28 F11.7 deg RAdeg W1 right ascension, if available;
otherwise W2 right ascension (J2000) (ra)
30- 40 F11.7 deg DEdeg W1 declination, if available;
otherwise W2 declination (J2000) (dec)
42- 49 F8.3 pix XposW1 [-0.5/2048] x coordinate in the W1 band (xW1)
51- 58 F8.3 pix XposW2 [-0.5/2048] x coordinate in the W2 band (xW2)
60- 67 F8.3 pix YposW1 [-0.5/2048] y coordinate in the W1 band (yW1)
69- 76 F8.3 pix YposW2 [-0.5/2048] y coordinate in the W2 band (yW2)
78- 89 E12.5 309.05nJy FW1 [-1337840/5.3E10] Flux in the W1 (3.4um) band
in "Vega nMgy" (fluxW1) (1)
91-102 E12.5 167.66nJy FW2 [-4367380/7E10] Flux in the W2 (4.6um) band
in "Vega nMgy" (fluxW2) (1)
104-128 F25.3 pix e_XposW1 [0/1E20] Uncertainty in XposW1 (dxW1)
130-154 F25.3 pix e_XposW2 [0/1E20] Uncertainty in XposW2 (dxW2)
156-180 F25.3 pix e_YposW1 [0/1E20] Uncertainty in YposW1 (dyW1)
182-206 F25.3 pix e_YposW2 [0/1E20] Uncertainty in YposW2 (dyW2)
208-218 E11.5 309.05nJy e_FW1 [0/1E10] Uncertainty in FW1
(statistical only) (dfluxW1) (1)
220-230 E11.5 167.66nJy e_FW2 [0/1E10] Uncertainty in FW2
(statistical only) (dflxW2) (1)
232-238 F7.5 --- q_W1 [0/1] Quality factor on W1 (1=good detection)
(qfW1) (2)
240-246 F7.5 --- q_W2 [0/1] Quality factor on W2 (1=good detection)
(qfW2) (2)
248-257 E10.4 --- rchi2W1 [0/3271100] Average chi square per pixel
on W1, weighted by PSF
259-268 E10.4 --- rchi2W2 [0/172620] Average ξ2 per pixel on W2,
weighted by PSF
270-277 F8.4 --- fFW1 [-64/564] Fraction of W1 flux in this
object's PSF that comes from this object
(fracfluxW1)
279-286 F8.4 --- fFW2 [-29.1/156.5] Fraction of W2 flux in this
object's PSF that comes from this object
(fracfluxW2)
288-299 E12.5 309.05nJy FW1lbs [-2.6E9/1.9E9] Local-background-subtracted W1
flux in "Vega nMgy" (fluxlbsW1) (1)
301-312 E12.5 167.66nJy FW2lbs [-1.2E10/2E10] Local-background-subtracted W2
flux in "Vega nMgy" (fluxlbsW2) (1)
314-324 E11.5 309.05nJy e_FW1lbs [0/2.5E9] Uncertainty in FW1lbs
(dfluxlbsW1) (1)
326-336 E11.5 167.66nJy e_FW2lbs [0/8E9] Uncertainty in FW2lbs
(dfluxlbsW2) (1)
338-343 F6.4 pix fwhmW1 [0/3] Full-width at half-maximum of PSF in W1
345-350 F6.4 pix fwhmW2 [0/3] Full-width at half-maximum of PSF in W2
352-364 E13.6 --- SpModW1 [-2844/2819] SExtractor spread_model
parameter on W1 (∼0=point source)
(spread_modelW1)
366-378 E13.6 --- SpModW2 [-20259/7281] SExtractor spread_model
parameter on W2 (∼0=point source)
(spread_modelW2)
380-391 E12.6 --- e_SpModW1 [0/3.1E8] Uncertainty in SpModW1
(dspread_modelW1)
393-408 F16.6 --- e_SpModW2 [0/5.3E8] Uncertainty in SpModW2
(dspread_modelW2)
410-421 E12.5 309.05nJy skyW1 [-7572/52355] Sky in W1 in "Vega nMgy" (1)
423-434 E12.5 167.66nJy skyW2 [-8322/54067] Sky in W2 in "Vega nMgy" (1)
436-446 F11.7 deg RAW1deg Right Ascension from individual-image
catalogs in W1 (ra12W1)
448-458 F11.7 deg RAW2deg Right Ascension from individual-image
catalogs in W2 (ra12W2)
460-470 F11.7 deg DEW1deg Declination from individual-image catalogs
in W1 (dec12W1)
472-482 F11.7 deg DEW2deg Declination from individual-image catalogs
in W2 (dec12W2)
484-491 A8 --- coaddID Coadd unique ID (coadd_id)
493-510 A18 --- detIDW1 ? Unique detection ID in W1 (unwise_detidW1)
512-529 A18 --- detIDW2 ? Unique detection ID in W2 (unwise_detidW2)
531-535 I5 --- nmW1 [0/23582] Number of single-exposure images of
this part of sky in coadd in W1
537-541 I5 --- nmW2 [0/23187] Number of single-exposure images of
this part of sky in coadd in W2
543-543 I1 --- PrimW1 [0/1] The center of this source is in the
primary region of its coadd in W1
(primary12W1)
545-545 I1 --- PrimW2 [0/1] The center of this source is in the
primary region of its coadd in W2
(primary12W2)
547-549 I3 --- FlagsW1 [0/249] unWISE Coadd Flags flags at central
pixel in W1 (flags_unwiseW1) (3)
551-553 I3 --- FlagsW2 [0/243] unWISE Coadd Flags flags at central
pixel W2 (flags_unwiseW2) (3)
555-557 I3 --- f_FlagsW1 [0/250] Additional informational flags at
central pixel in W1 (flags_infoW1) (4)
559-561 I3 --- f_FlagsW2 [0/250] Additional informational flags at
central pixel in W2 (flags_infoW2) (4)
563-563 I1 --- Prim [0/1] W1 primary status, if available;
otherwise W2 primary status (primary1)
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Note (1): All fluxes are in Vega nanomaggies (nMgy; Finkbeiner+
2004AJ....128.2577F 2004AJ....128.2577F), so that the Vega magnitude of a source is given
by 22.5-2.5log(flux). The absolute calibration is ultimately inherited
from AllWISE through the calibration of Meisner+ (2017AJ....154..161M 2017AJ....154..161M).
This inheritance depends on details of the PSF normalization at large
radii, which is uncertain. To improve the agreement between unWISE and
AllWISE fluxes, we recommend subtracting 4mmag from unWISE W1 and
32mmag from unWISE W2 fluxes.
Corresponding AB magnitudes are given by the following equations:
mW1,AB=mW1,Vega+2.699
mW2,AB=mW2,Vega+3.339
Following these conversion laws, columns in nanomaggies were
determined by CDS staff to be in units of 309.05nJy and 167.66nJy
for W1 and W2, respectively.
Note (2): The "quality factor" is a concept inherited from PS1. It tabulates
the PSF-weighted fraction of pixels contributing to this detection.
Good detections will have quality factors close to one. Heavily
saturated detections will have quality factors close to zero.
Note (3): The unWISE flags simply give the value of the unWISE mask image for
the central pixel of the unWISE catalog source, after "collapsing" the
time-resolved masks into a smaller number of bits appropriate for
static sources. All bits mark features of very bright stars. These
flags are described in more detail here: http://catalog.unwise.me/
files/unwisebitmaskwriteup-03Dec2018.pdf
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Bit Description
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0 In core or wings
1 In diffraction spike
2 In ghost
3 In first latent
4 In second latent
5 In circular halo
6 Saturated
7 In geometric diffraction spike
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Note (4): The unWISE info flags contain additional fields related to the
crowdsource processing or unWISE coadd bright star mask.
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Bit Description
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0 In PSF of bright star falling off coadd
1 In HyperLeda large galaxy
2 In "big object" (e.g., a Magellanic cloud)
3 Pixel may contain the centroid of a very bright star
4 crowdsource considers this pixel potentially affected by saturation
5 Pixel may contain nebulosity
6 Sources in this pixel will not be aggressively deblended
7 Candidate sources in this pixel must be "sharp" to be optimized
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History:
Downloaded from http://catalog.unwise.me/catalogs.html
(End) F.-X. Pineau, E. Perret [CDS] 17-Feb-2020