- ID:
- ivo://CDS.VizieR/J/ApJ/755/47
- Title:
- Murchison Widefield Array 110-200MHz observations
- Short Name:
- J/ApJ/755/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Murchison Widefield Array (MWA) is a new low-frequency, wide field-of-view radio interferometer under development at the Murchison Radio-astronomy Observatory in Western Australia. We have used a 32 element MWA prototype interferometer (MWA-32T) to observe two 50{deg} diameter fields in the southern sky, covering a total of ~2700deg^2^, in order to evaluate the performance of the MWA-32T, to develop techniques for epoch of reionization experiments, and to make measurements of astronomical foregrounds. We developed a calibration and imaging pipeline for the MWA-32T, and used it to produce ~15' angular resolution maps of the two fields in the 110-200MHz band. We perform a blind source extraction using these confusion-limited images, and detect 655 sources at high significance with an additional 871 lower significance source candidates. We compare these sources with existing low-frequency radio surveys in order to assess the MWA-32T system performance, wide-field analysis algorithms, and catalog quality. Our source catalog is found to agree well with existing low-frequency surveys in these regions of the sky and with statistical distributions of point sources derived from Northern Hemisphere surveys; it represents one of the deepest surveys to date of this sky field in the 110-200MHz band.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/621/A107
- Title:
- MUSE-Wide Lyman alpha luminosity function 3<z<6
- Short Name:
- J/A+A/621/A107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the Lyman{alpha} emitter (LAE) luminosity function (LF) within the redshift range 2.9<=z<=6 from the first instalment of the blind integral field spectroscopic MUSE-Wide survey. This initial part of the survey probes a region of 22.2arcmin^2^ in the CANDELS/GOODS-S field (24 MUSE pointings with 1h integrations). The dataset provided us with 237 LAEs from which we construct the LAE LF in the luminosity range 42.2<=logL_Ly{alpha}_[erg/s]<=43.5 within a volume of 2.3x10^5^Mpc^3^. For the LF construction we utilise three different non-parametric estimators: the classical 1/V_max_ method, the C^-^ method, and an improved binned estimator for the differential LF. All three methods deliver consistent results, with the cumulative LAE LF being {Phi}(logL_Ly{alpha}_[erg/s]=43.5)~=3x10^-6^Mpc^-3^ and {Phi}(logL_Ly{alpha}_[erg/s]=42.2)~=2x10^-3^Mpc^-3^ towards the bright and faint end of our survey, respectively. By employing a non-parametric statistical test, and by comparing the full sample to subsamples in redshift bins, we find no supporting evidence for an evolving LAE LF over the probed redshift and luminosity range. Using a parametric maximum-likelihood technique we determine the best-fitting Schechter function parameters {alpha}=-1.84^+0.42^_-0.41_ and logL^*^[erg/s]=42.2^+0.22^_-0.16_ with the corresponding normalisation log{phi}^*^[Mpc^-3^]=-2.71. However, the dynamic range in Ly{alpha} luminosities probed by MUSE-Wide leads to a strong degeneracy between {alpha} and L^*^. Moreover, we find that a power-law parametrisation of the LF appears to be less consistent with the data compared to the Schechter function, even so when not excluding the X-Ray identified AGN from the sample. When correcting for completeness in the LAE LF determinations, we take into account that LAEs exhibit diffuse extended low surface brightness halos. We compare the resulting LF to one obtained by applying a correction assuming compact point-like emission. We find that the standard correction underestimates the LAE LF at the faint end of our survey by a factor of 2.5. Contrasting our results to the literature we find that at logL_Ly{alpha}_[erg/s]~<42.5 previous LAE LF determinations from narrow-band surveys appear to be affected by a similar bias.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A141
- Title:
- MUSE-Wide Survey DR1 catalog
- Short Name:
- J/A+A/624/A141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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 100x1arcmin^2^ 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 (Bacon et al., 2017A&A...608A...1B). 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-{alpha} (Lya) 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 {Delta}z~=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 Lya emitters yields no signal; the Lya population is not dominated by even low luminosity AGN. Other cross-matches of our emission-line catalog to radio and submm 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 website https://musewide.aip.de.
- ID:
- ivo://CDS.VizieR/J/A+A/606/A12
- Title:
- MUSE-Wide survey: 831 emission line galaxies
- Short Name:
- J/A+A/606/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a first instalment of the MUSE-Wide survey, covering an area of 22.2 arcmin^2^ (corresponding to ~20% of the final survey) in the CANDELS/Deep area of the Chandra Deep Field South. We use the MUSE integral field spectrograph at the ESO VLT to conduct a full-area spectroscopic mapping at a depth of 1h exposure time per 1-arcmin^2^ pointing. We searched for compact emission line objects using our newly developed LSDCat software based on a 3-D matched filtering approach, followed by interactive classification and redshift measurement of the sources. Our catalogue contains 831 distinct emission line galaxies with redshifts ranging from 0.04 to 6. Roughly one third (237) of the emission line sources are Lyman{alpha} emitting galaxies with 3<z<6, only four of which had previously measured spectroscopic redshifts. At lower redshifts 351 galaxies are detected primarily by their [OII] emission line (0.3<~z<~1.5), 189 by their [OIII] line (0.21<~z<~0.85), and 46 by their H{alpha} line (0.04<~z<~0.42). Comparing our spectroscopic redshifts to photometric redshift estimates from the literature, we find excellent agreement for z<1.5 with a median {Delta}z of only ~4x10^-4^ and an outlier rate of 6%, however a significant systematic offset of {Delta}z=0.26 and an outlier rate of 23% for Ly{alpha} emitters at z>3. Together with the catalogue we also release 1D PSF-weighted extracted spectra and small 3D datacubes centred on each of the 831 sources.
- ID:
- ivo://CDS.VizieR/J/ApJS/248/24
- Title:
- MUSTANG-2 Galactic Plane survey at 3mm (MGPS90)
- Short Name:
- J/ApJS/248/24
- Date:
- 04 Dec 2021
- Publisher:
- CDS
- Description:
- We report the results of a pilot program for a Green Bank Telescope MUSTANG-2 Galactic Plane survey at 3mm (90GHz), MGPS90. The survey achieves a typical 1{sigma} depth of 1-2mJy/beam with a 9" beam. We describe the survey parameters, quality assessment process, cataloging, and comparison with other data sets. We have identified 709 sources over seven observed fields selecting some of the most prominent millimeter-bright regions between 0{deg}<l<50{deg} (total area ~7.5deg^2^). The majority of these sources have counterparts at other wavelengths. By applying flux selection criteria to these sources, we successfully recovered several known hypercompact HII (HCHII) regions but did not confirm any new ones. We identify 126 sources that have mm-wavelength counterparts but do not have cm-wavelength counterparts and are therefore candidate HCHII regions; of these, 10 are morphologically compact and are strong candidates for new HCHII regions. Given the limited number of candidates in the extended area in this survey compared to the relatively large numbers seen in protoclusters W51 and W49, it appears that most HCHII regions exist within dense protoclusters. Comparing the counts of HCHII to ultracompact HII (UCHII) regions, we infer the HCHII region lifetime is 16%-46% that of the UCHII region lifetime. We additionally separated the 3mm emission into dust and free-free emission by comparing with archival 870{mu}m and 20cm data. In the selected pilot fields, most (>~80%) of the 3mm emission comes from plasma, either through free-free or synchrotron emission.
- ID:
- ivo://CDS.VizieR/J/AJ/134/1103
- Title:
- MUSYC deep near-infrared imaging
- Short Name:
- J/AJ/134/1103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep near-infrared JHK imaging of four 10x10 fields. The observations were carried out as part of the Multiwavelength Survey by Yale-Chile (MUSYC) with ISPI on the CTIO 4m telescope. The typical point-source limiting depths are J~22.5, H~21.5, and K~21 (5{sigma}; Vega). The effective seeing in the final images is 1.0". We combine these data with MUSYC UBVRIz imaging to create K-selected catalogs that are unique for their uniform size, depth, filter coverage, and image quality.
- ID:
- ivo://CDS.VizieR/J/ApJS/189/270
- Title:
- MUSYC optical imaging in ECDF-S
- Short Name:
- J/ApJS/189/270
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep optical 18-medium-band photometry from the Subaru telescope over the ~30'x30' Extended Chandra Deep Field-South, as part of the Multiwavelength Survey by Yale-Chile (MUSYC). This field has a wealth of ground- and space-based ancillary data, and contains the GOODS-South field and the Hubble Ultra Deep Field. We combine the Subaru imaging with existing UBVRIzJHK and Spitzer IRAC images to create a uniform catalog. Detecting sources in the MUSYC "BVR" image we find ~40,000 galaxies with R_AB_<25.3, the median 5{sigma} limit of the 18 medium bands. Photometric redshifts are determined using the EAzY code and compared to ~2000 spectroscopic redshifts in this field. The medium-band filters provide very accurate redshifts for the (bright) subset of galaxies with spectroscopic redshifts, particularly at 0.1<z<1.2 and at z~>3.5. For 0.1<z<1.2, we find a 1{sigma} scatter in {DELTA}z/(1+z) of 0.007, similar to results obtained with a similar filter set in the COSMOS field. As a demonstration of the data quality, we show that the red sequence and blue cloud can be cleanly identified in rest-frame color-magnitude diagrams at 0.1<z<1.2. We find that ~20% of the red sequence galaxies show evidence of dust emission at longer rest-frame wavelengths. The reduced images, photometric catalog, and photometric redshifts are provided through the public MUSYC Web site (http://www.astro.yale.edu/MUSYC/).
- ID:
- ivo://CDS.VizieR/J/ApJ/833/193
- Title:
- MYStIX candidate protostars
- Short Name:
- J/ApJ/833/193
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Massive Young Star-Forming Complex in Infrared and X-ray (MYStIX) project provides a new census on stellar members of massive star-forming regions within 4kpc. Here the MYStIX Infrared Excess catalog and Chandra-based X-ray photometric catalogs are mined to obtain high-quality samples of Class I protostars using criteria designed to reduce extragalactic and Galactic field star contamination. A total of 1109 MYStIX Candidate Protostars (MCPs) are found in 14 star-forming regions. Most are selected from protoplanetary disk infrared excess emission, but 20% are found from their ultrahard X-ray spectra from heavily absorbed magnetospheric flare emission. Two-thirds of the MCP sample is newly reported here. The resulting samples are strongly spatially associated with molecular cores and filaments on Herschel far-infrared maps. This spatial agreement and other evidence indicate that the MCP sample has high reliability with relatively few "false positives" from contaminating populations. But the limited sensitivity and sparse overlap among the infrared and X-ray subsamples indicate that the sample is very incomplete with many "false negatives." Maps, tables, and source descriptions are provided to guide further study of star formation in these regions. In particular, the nature of ultrahard X-ray protostellar candidates without known infrared counterparts needs to be elucidated.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A116
- Title:
- Nainital-Cape Survey. IV.
- Short Name:
- J/A+A/590/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Nainital-Cape Survey is a dedicated ongoing Survey programme to search for and study pulsational variability in chemically peculiar (CP) stars to understand their internal structure and evolution. The main aims of this Survey are to find new pulsating Ap and Am stars in the northern and southern hemisphere and to perform asteroseismic studies of these new pulsators. The Survey is conducted using high-speed photometry. The candidate stars were selected on the basis of having Stromgren photometric indices similar to those of known pulsating CP stars. Over the last decade a total of 337 candidate pulsating CP stars were observed for the Nainital-Cape Survey, making it one of the longest ground-based surveys for pulsation in CP stars in terms of time span and sample size. The previous papers of this series presented seven new pulsating variables and 229 null results. In this paper we present the light curves, frequency spectra and various astrophysical parameters of the 108 additional CP stars observed since the last reported results. We also tabulated the basic physical parameters of the known roAp stars. As a part of establishing the detection limits in the Nainital-Cape Survey, we investigated the scintillation noise level at the two observing sites used in this Survey, Sutherland and Nainital, by comparing the combined frequency spectra stars observed from each location. Our analysis shows that both the sites permit the detection of variations of the order of 0.6-milli-magnitude (mmag) in the frequency range 1-4mHz, Sutherland is on average marginally better.
- ID:
- ivo://CDS.VizieR/J/ApJS/166/128
- Title:
- Narrow line Seyfert 1 galaxies from SDSS-DR3
- Short Name:
- J/ApJS/166/128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out a systematic search for narrow line Seyfert 1 galaxies (NLS1s) from objects assigned as "QSOs" or "galaxies" in the spectroscopic sample of the Sloan Digital Sky Survey Data Release 3 (SDSS DR3) by a careful modeling of their emission lines and continua. The result is a uniform sample comprising ~2000 NLS1s. This sample dramatically increases the number of known NLS1s by a factor of ~10 over previous compilations. This paper presents the parameters of the prominent emission lines and continua, which were measured accurately with typical uncertainties <10%. Taking advantage of such an unprecedented large and uniform sample with accurately measured spectral parameters, we carried out various statistical analyses, some of which were only possible for the first time.
