The LOFAR Two-metre Sky Survey Deep Fields: Data release 1. IV. Photometric redshifts and stellar masses

We present the MUSE-Wide survey, a blind, 3D spectroscopic survey in the CANDELS/GOODS-S and CANDELS/COSMOS regions. The final survey will cover 100 × 1 arcmin2 MUSE fields. Each MUSE-Wide pointing has a depth of one hour and hence targets more extreme and more luminous objects over ten times the area of the MUSE-Deep fields. The legacy value of MUSE-Wide lies in providing “spectroscopy of everything” without photometric pre-selection. We describe the data reduction, post-processing and PSF characterization of the first 44 CANDELS/GOODS-S MUSE-Wide pointings released with this publication. Using a 3D matched filtering approach we detect 1602 emission line sources, including 479 Lyman-α (Lyα) emitting galaxies with redshifts 2.9 ≲ z ≲ 6.3. We cross-matched the emission line sources to existing photometric catalogs, finding almost complete agreement in redshifts (photometric and spectroscopic) and stellar masses for our low redshift (z < 1.5) emitters. At high redshift, we only find ∼55% matches to photometric catalogs. We encounter a higher outlier rate and a systematic offset of Δz ≃ 0.2 when comparing our MUSE redshifts with photometric redshifts from the literature. Cross-matching the emission line sources with X-ray catalogs from the Chandra Deep Field South, we find 127 matches, mostly in agreement with the literature redshifts, including ten objects with no prior spectroscopic identification. Stacking X-ray images centered on our Lyα emitters yields no signal; the Lyα population is not dominated by even low luminosity AGN. Other cross-matches of our emission-line catalog to radio and submillimeter data, yielded far lower numbers of matches, most of which already were covered by the X-ray catalog. A total of 9205 photometrically selected objects from the CANDELS survey lie in the MUSE-Wide footprint, of which we provide optimally extracted 1D spectra. We are able to determine the spectroscopic redshift of 98% of 772 photometrically selected galaxies brighter than 24th F775W magnitude. All the data in the first data release - datacubes, catalogs, extracted spectra, maps - are available on the MUSE-Wide data release webpage.

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The LOFAR Two-metre Sky Survey

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833562 ◽

2019 ◽

Vol 622 ◽

pp. A3 ◽

Cited By ~ 18

Author(s):

K. J. Duncan ◽

J. Sabater ◽

H. J. A. Röttgering ◽

M. J. Jarvis ◽

D. J. B. Smith ◽

...

Keyword(s):

Radio Continuum ◽

Optical Data ◽

Source Population ◽

Wide Field ◽

Radio Luminosity ◽

Photometric Redshifts ◽

Mid Infrared ◽

Strong Trend ◽

Sky Survey ◽

Data Release

The LOFAR Two-metre Sky Survey (LoTSS) is a sensitive, high-resolution 120–168 MHz survey of the Northern sky. The LoTSS First Data Release (DR1) presents 424 square degrees of radio continuum observations over the HETDEX Spring Field (10h45m00s < right ascension < 15h30m00s and 45°00′00″ < declination < 57°00′00″) with a median sensitivity of 71 μJy beam−1 and a resolution of 6″. In this paper we present photometric redshifts (photo-z) for 94.4% of optical sources over this region that are detected in the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) 3π steradian survey. Combining the Pan-STARRS optical data with mid-infrared photometry from the Wide-field Infrared Survey Explorer, we estimate photo-zs using a novel hybrid photometric redshift methodology optimised to produce the best possible performance for the diverse sample of radio continuum selected sources. For the radio-continuum detected population, we find an overall scatter in the photo-z of 3.9% and an outlier fraction (|zphot−zspec|/(1 + zspec) > 0.15) of 7.9%. We also find that, at a given redshift, there is no strong trend in photo-z quality as a function of radio luminosity. However there are strong trends as a function of redshift for a given radio luminosity, a result of selection effects in the spectroscopic sample and/or intrinsic evolution within the radio source population. Additionally, for the sample of sources in the LoTSS First Data Release with optical counterparts, we present rest-frame optical and mid-infrared magnitudes based on template fits to the consensus photometric (or spectroscopic when available) redshift.

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The LOFAR Two-metre Sky Survey

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833559 ◽

2019 ◽

Vol 622 ◽

pp. A1 ◽

Cited By ~ 104

Author(s):

T. W. Shimwell ◽

C. Tasse ◽

M. J. Hardcastle ◽

A. P. Mechev ◽

W. L. Williams ◽

...

Keyword(s):

Radio Continuum ◽

Host Galaxies ◽

Positional Accuracy ◽

Photometric Redshifts ◽

Sky Survey ◽

Public Data ◽

Data Release ◽

Scientific Potential ◽

Optical Identifications ◽

Right Ascension

The LOFAR Two-metre Sky Survey (LoTSS) is an ongoing sensitive, high-resolution 120–168 MHz survey of the entire northern sky for which observations are now 20% complete. We present our first full-quality public data release. For this data release 424 square degrees, or 2% of the eventual coverage, in the region of the HETDEX Spring Field (right ascension 10h45m00s to 15h30m00s and declination 45°00′00″ to 57°00′00″) were mapped using a fully automated direction-dependent calibration and imaging pipeline that we developed. A total of 325 694 sources are detected with a signal of at least five times the noise, and the source density is a factor of ∼10 higher than the most sensitive existing very wide-area radio-continuum surveys. The median sensitivity is S144 MHz = 71 μJy beam−1 and the point-source completeness is 90% at an integrated flux density of 0.45 mJy. The resolution of the images is 6″ and the positional accuracy is within 0.2″. This data release consists of a catalogue containing location, flux, and shape estimates together with 58 mosaic images that cover the catalogued area. In this paper we provide an overview of the data release with a focus on the processing of the LOFAR data and the characteristics of the resulting images. In two accompanying papers we provide the radio source associations and deblending and, where possible, the optical identifications of the radio sources together with the photometric redshifts and properties of the host galaxies. These data release papers are published together with a further ∼20 articles that highlight the scientific potential of LoTSS.

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Photometric redshifts and k-corrections for the Sloan Digital Sky Survey Data Release 7

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2011.18222.x ◽

2011 ◽

Vol 413 (2) ◽

pp. 1395-1408 ◽

Cited By ~ 23

Author(s):

Ana Laura O'Mill ◽

Fernanda Duplancic ◽

Diego García Lambas ◽

Laerte Sodré Jr

Keyword(s):

Survey Data ◽

Sloan Digital Sky Survey ◽

Photometric Redshifts ◽

Sky Survey ◽

Data Release

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The LOFAR Two Metre Sky Survey: Deep Fields Data Release 1. III. Host-galaxy identifications and value added catalogues

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038813 ◽

2020 ◽

Author(s):

R. Kondapally ◽

P. N. Best ◽

M. J. Hardcastle ◽

Keyword(s):

Value Added ◽

Host Galaxy ◽

Sky Survey ◽

Data Release ◽

Deep Fields

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Testing homogeneity in the Sloan Digital Sky Survey Data Release Twelve with Shannon entropy

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stv2166 ◽

2015 ◽

Vol 454 (3) ◽

pp. 2647-2656 ◽

Cited By ~ 16

Author(s):

Biswajit Pandey ◽

Suman Sarkar

Keyword(s):

Survey Data ◽

Shannon Entropy ◽

Sloan Digital Sky Survey ◽

Sky Survey ◽

Data Release ◽

Testing Homogeneity

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A New Catalog of Isolated Galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310007064 ◽

2009 ◽

Vol 5 (S267) ◽

pp. 464-464

Author(s):

J. A. Vázquez-Mata ◽

H. M. Hernández-Toledo ◽

Changbom Park ◽

Yun-Young Choi

Keyword(s):

Galaxy Formation ◽

Environmental Effects ◽

Comparative Studies ◽

Sloan Digital Sky Survey ◽

Selection Algorithm ◽

Isolated Galaxies ◽

Galaxy Formation And Evolution ◽

Sky Survey ◽

Data Release ◽

Formation And Evolution

We present a new catalog of isolated galaxies (coined as UNAM–KIAS) obtained through an automated systematic search. The 1520 isolated galaxies were found in ~ 1.4 steradians of the sky in the Sloan Digital Sky Survey Data Release 5 (SDSS DR5) photometry. The selection algorithm was implemented from a variation of the criteria developed by Karachentseva (1973), with full redshift information. This new catalog is aimed to carry out comparative studies of environmental effects and constraining the currently competing scenarios of galaxy formation and evolution.

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Hierarchical Matching and Regression with Application to Photometric Redshift Estimation

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317001569 ◽

2016 ◽

Vol 12 (S325) ◽

pp. 145-155

Author(s):

Fionn Murtagh

Keyword(s):

Information Structure ◽

Data Analytics ◽

A Priori ◽

Sloan Digital Sky Survey ◽

Photometric Redshifts ◽

Merging Galaxies ◽

Photometric Redshift ◽

Sky Survey ◽

Wide Range ◽

Regression Problems

AbstractThis work emphasizes that heterogeneity, diversity, discontinuity, and discreteness in data is to be exploited in classification and regression problems. A global a priori model may not be desirable. For data analytics in cosmology, this is motivated by the variety of cosmological objects such as elliptical, spiral, active, and merging galaxies at a wide range of redshifts. Our aim is matching and similarity-based analytics that takes account of discrete relationships in the data. The information structure of the data is represented by a hierarchy or tree where the branch structure, rather than just the proximity, is important. The representation is related to p-adic number theory. The clustering or binning of the data values, related to the precision of the measurements, has a central role in this methodology. If used for regression, our approach is a method of cluster-wise regression, generalizing nearest neighbour regression. Both to exemplify this analytics approach, and to demonstrate computational benefits, we address the well-known photometric redshift or ‘photo-z’ problem, seeking to match Sloan Digital Sky Survey (SDSS) spectroscopic and photometric redshifts.

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