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Register a new userThe MUSE-Wide Survey: Survey Description and First Data Release
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We present the MUSE-Wide survey, a blind, 3D spectroscopic survey in the CANDELS/GOODS-S and CANDELS/COSMOS regions. Each MUSE-Wide pointing has a depth of 1 hour and hence targets more extreme and more luminous objects over 10 times the area of the MUSE-Deep fields (Bacon et al. 2017). 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 detected 1,602 emission line sources, including 479 Lyman-$alpha$ (Lya) emitting galaxies with redshifts $2.9 lesssim z lesssim 6.3$. We cross-match the emission line sources to existing photometric catalogs, finding almost complete agreement in redshifts 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$simeq$0.2 when comparing our MUSE redshifts with photometric redshifts. Cross-matching the emission line sources with X-ray catalogs from the Chandra Deep Field South, we find 127 matches, including 10 objects with no prior spectroscopic identification. Stacking X-ray images centered on our Lya emitters yielded no signal; the Lya population is not dominated by even low luminosity AGN. A total of 9,205 photometrically selected objects from the CANDELS survey lie in the MUSE-Wide footprint, which we provide optimally extracted 1D spectra of. 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. [abridged]
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We present an overview of the CMZoom survey and its first data release. CMZoom is the first blind, high-resolution survey of the Central Molecular Zone (CMZ; the inner 500 pc of the Milky Way) at wavelengths sensitive to the pre-cursors of high-mass stars. CMZoom is a 500-hour Large Program on the Submillimeter Array (SMA) that mapped at 1.3 mm all of the gas and dust in the CMZ above a molecular hydrogen column density of 10^23 cm^-2 at a resolution of ~3 (0.1 pc). In this paper, we focus on the 1.3 mm dust continuum and its data release, but also describe CMZoom spectral line data which will be released in a forthcoming publication. While CMZoom detected many regions with rich and complex substructure, its key result is an overall deficit in compact substructures on 0.1 - 2 pc scales (the compact dense gas fraction: CDGF). In comparison with clouds in the Galactic disk, the CDGF in the CMZ is substantially lower, despite having much higher average column densities. CMZ clouds with high CDGFs are well-known sites of active star formation. The inability of most gas in the CMZ to form compact substructures is likely responsible for the dearth of star formation in the CMZ, surprising considering its high density. The factors responsible for the low CDGF are not yet understood but are plausibly due to the extreme environment of the CMZ, having far-reaching ramifications for our understanding of the star formation process across the cosmos.
We present the MUSE Hubble Ultra Deep Survey, a mosaic of nine MUSE fields covering 90% of the entire HUDF region with a 10-hour deep exposure time, plus a deeper 31-hour exposure in a single 1.15 arcmin2 field. The improved observing strategy and advanced data reduction results in datacubes with sub-arcsecond spatial resolution (0.65 arcsec at 7000 A) and accurate astrometry (0.07 arcsec rms). We compare the broadband photometric properties of the datacubes to HST photometry, finding a good agreement in zeropoint up to mAB=28 but with an increasing scatter for faint objects. We have investigated the noise properties and developed an empirical way to account for the impact of the correlation introduced by the 3D drizzle interpolation. The achieved 3 sigma emission line detection limit for a point source is 1.5 and 3.1 10-19 erg.s-1.cm-2 for the single ultra-deep datacube and the mosaic, respectively. We extracted 6288 sources using an optimal extraction scheme that takes the published HST source locations as prior. In parallel, we performed a blind search of emission line galaxies using an original method based on advanced test statistics and filter matching. The blind search results in 1251 emission line galaxy candidates in the mosaic and 306 in the ultradeep datacube, including 72 sources without HST counterparts (mAB>31). In addition 88 sources missed in the HST catalog but with clear HST counterparts were identified. This data set is the deepest spectroscopic survey ever performed. In just over 100 hours of integration time, it provides nearly an order of magnitude more spectroscopic redshifts compared to the data that has been accumulated on the UDF over the past decade. The depth and high quality of these datacubes enables new and detailed studies of the physical properties of the galaxy population and their environments over a large redshift range.
The Green Bank Telescope (GBT) Diffuse Ionized Gas Survey (GDIGS) traces ionized gas in the Galactic midplane by measuring $4-8$GHz radio recombination line (RRL) emission. The nominal survey zone is $32.3^{circ}> l >-5^{circ}$, $|b|<0.5^{circ}$, but coverage extends above and below the plane in select fields, and additionally includes the areas around W47 ($l simeq 37.5^{circ}$) and W49 ($l simeq 43^{circ}$). GDIGS simultaneously observes 22 Hn$alpha$ (15 usable), 25 Hn$beta$ (18 usable), and 8 Hn$gamma$ RRLs (all usable), as well as multiple molecular line transitions (including of H$_2^{13}$CO, H$_2$CO, and CH$_3$OH). Here, we describe the GDIGS survey parameters and characterize the RRL data, focusing primarily on the Hn$alpha$ data. We produce sensitive data cubes by averaging the usable RRLs, after first smoothing to a common spectral resolution of 0.5km/s and a spatial resolution of 2.65 for Hn$alpha$, 2.62 for Hn$beta$, and 2.09 for Hn$gamma$. The average spectral noise per spaxel in the hna data cubes is $sim!10$mK ($sim!5$mJy/beam). This sensitivity allows GDIGS to detect RRLs from plasma throughout the inner Galaxy. The GDIGS Hn$alpha$ data are sensitive to emission measures $EM gtrsim 1100$cm$^{-6}$pc, which corresponds to a mean electron density $langle n_e rangle gtrsim 30$cm$^{-3}$ for a 1pc path length or $langle n_e rangle gtrsim 1$cm$^{-3}$ for a 1kpc path length.
The Parkes Galactic All-Sky Survey (GASS) is a survey of Galactic atomic hydrogen (HI) emission in the Southern sky covering declinations $delta leq 1^{circ}$ using the Parkes Radio Telescope. The survey covers $2pi$ steradians with an effective angular resolution of ~16, at a velocity resolution of 1.0 km/s, and with an rms brightness temperature noise of 57 mK. GASS is the most sensitive, highest angular resolution survey of Galactic HI emission ever made in the Southern sky. In this paper we outline the survey goals, describe the observations and data analysis, and present the first-stage data release. The data product is a single cube at full resolution, not corrected for stray radiation. Spectra from the survey and other data products are publicly available online.
LOFAR is the only radio telescope that is presently capable of high-sensitivity, high-resolution (<1 mJy/b and <15) observations at ultra-low frequencies (<100 MHz). To utilise these capabilities, the LOFAR Surveys Key Science Project is undertaking a large survey to cover the entire northern sky with Low Band Antenna (LBA) observations. The LOFAR LBA Sky Survey (LoLSS) aims to cover the entire northern sky with 3170 pointings in the frequency range 42-66 MHz, at a resolution of 15 arcsec and at a sensitivity of 1 mJy/b. Here we outline the survey strategy, the observational status, the current calibration techniques, and briefly describe several scientific motivations. We also describe the preliminary public data release. The preliminary images were produced using a fully automated pipeline that aims to correct all direction-independent effects in the data. Whilst the direction-dependent effects, such as those from the ionosphere, are not yet corrected, the images presented in this work are still 10 times more sensitive than previous surveys available at these low frequencies. The preliminary data release covers 740 sqdeg around the HETDEX spring field region at a resolution of 47 with a median noise level of 5 mJy/b. The images and the catalogue with 25,247 sources are publicly released. We demonstrate that the system is capable of reaching an rms noise of 1 mJy/b and the resolution of 15 once direction-dependent effects are corrected for. LoLSS will provide the ultra-low-frequency information for hundreds of thousands of radio sources, providing critical spectral information and producing a unique dataset that can be used for a wide range of science topics such as: the search for high redshift galaxies and quasars, the study of the magnetosphere of exoplanets, and the detection of the oldest populations of cosmic-rays in galaxies, clusters of galaxies, and from AGN activity.
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