12 research outputs found
The MUSE Hubble Ultra Deep Field Survey:II. Spectroscopic redshifts and comparisons to color selections of high-redshift galaxies
We have conducted a two-layered spectroscopic survey (1'x1' ultra deep and 3'x3' deep regions) in the Hubble Ultra Deep Field (HUDF) with the Multi Unit Spectroscopic Explorer (MUSE). The combination of a large field of view, high sensitivity, and wide wavelength coverage provides an order of magnitude improvement in spectroscopically confirmed redshifts in the HUDF; i.e., 1206 secure spectroscopic redshifts for HST continuum selected objects, which corresponds to 15% of the total (7904). The redshift distribution extends well beyond z>3 and to HST/F775W magnitudes as faint as ~30 mag (AB, 1-sigma). In addition, 132 secure redshifts were obtained for sources with no HST counterparts that were discovered in the MUSE data cubes by a blind search for emission-line features. In total, we present 1338 high quality redshifts, which is a factor of eight increase compared with the previously known spectroscopic redshifts in the same field. We assessed redshifts mainly with the spectral features [OII] at z~20% up to 28-29 mag and ~27 mag, respectively. We used the determined redshifts to test continuum color selection (dropout) diagrams of high-z galaxies. The selection condition for F336W dropouts successfully captures ~80% of the targeted z~2.7 galaxies. However, for higher redshift selections (F435W, F606W, and F775W dropouts), the success rates decrease to ~20-40%. We empirically redefine the selection boundaries to make an attempt to improve them to ~60%. The revised boundaries allow bluer colors that capture Lya emitters with high Lya equivalent widths falling in the broadbands used for the color-color selection. Along with this paper, we release the redshift and line flux catalog
The MUSE Hubble Ultra Deep Field Survey:II. Spectroscopic redshifts and comparisons to color selections of high-redshift galaxies
We have conducted a two-layered spectroscopic survey (1'x1' ultra deep and
3'x3' deep regions) in the Hubble Ultra Deep Field (HUDF) with the Multi Unit
Spectroscopic Explorer (MUSE). The combination of a large field of view, high
sensitivity, and wide wavelength coverage provides an order of magnitude
improvement in spectroscopically confirmed redshifts in the HUDF; i.e., 1206
secure spectroscopic redshifts for HST continuum selected objects, which
corresponds to 15% of the total (7904). The redshift distribution extends well
beyond z>3 and to HST/F775W magnitudes as faint as ~30 mag (AB, 1-sigma). In
addition, 132 secure redshifts were obtained for sources with no HST
counterparts that were discovered in the MUSE data cubes by a blind search for
emission-line features. In total, we present 1338 high quality redshifts, which
is a factor of eight increase compared with the previously known spectroscopic
redshifts in the same field. We assessed redshifts mainly with the spectral
features [OII] at z<1.5 (473 objects) and Lya at 2.9<z<6.7 (692 objects). With
respect to F775W magnitude, a 50% completeness is reached at 26.5 mag for ultra
deep and 25.5 mag for deep fields, and the completeness remains >~20% up to
28-29 mag and ~27 mag, respectively. We used the determined redshifts to test
continuum color selection (dropout) diagrams of high-z galaxies. The selection
condition for F336W dropouts successfully captures ~80% of the targeted z~2.7
galaxies. However, for higher redshift selections (F435W, F606W, and F775W
dropouts), the success rates decrease to ~20-40%. We empirically redefine the
selection boundaries to make an attempt to improve them to ~60%. The revised
boundaries allow bluer colors that capture Lya emitters with high Lya
equivalent widths falling in the broadbands used for the color-color selection.
Along with this paper, we release the redshift and line flux catalog.Comment: 26 pages, 26 figures, 4 tables, accepted for publication in A&A (MUSE
UDF Series Paper II), the redshift catalogs will be available at the CD
The Wide-field Spectroscopic Telescope (WST) Science White Paper
The Wide-field Spectroscopic Telescope (WST) is proposed as a new facility dedicated to the efficient delivery of spectroscopic surveys. This white paper summarises the initial concept as well as the corresponding science cases. WST will feature simultaneous operation of a large field-of-view (3 sq. degree), a high multiplex (20,000) multi-object spectrograph (MOS) and a giant 3x3 sq. arcmin integral field spectrograph (IFS). In scientific capability these requirements place WST far ahead of existing and planned facilities. Given the current investment in deep imaging surveys and noting the diagnostic power of
spectroscopy, WST will fill a crucial gap in astronomical capability and work synergistically with future ground and space-based facilities. This white paper shows that WST can address outstanding scientific questions in the areas of cosmology; galaxy assembly, evolution, and enrichment, including our own Milky Way; origin of stars and planets; time domain and multi-messenger astrophysics. WST's uniquely rich dataset will deliver unforeseen discoveries in many of these areas. The WST Science Team (already including more than 500 scientists worldwide) is open to the all astronomical community. To register in the WST Science Team please visit https://www.wstelescope.com/for-scientists/participat
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Euclid. I. Overview of the Euclid mission
The current standard model of cosmology successfully describes a variety ofmeasurements, but the nature of its main ingredients, dark matter and darkenergy, remains unknown. Euclid is a medium-class mission in the Cosmic Vision2015-2025 programme of the European Space Agency (ESA) that will providehigh-resolution optical imaging, as well as near-infrared imaging andspectroscopy, over about 14,000 deg^2 of extragalactic sky. In addition toaccurate weak lensing and clustering measurements that probe structureformation over half of the age of the Universe, its primary probes forcosmology, these exquisite data will enable a wide range of science. This paperprovides a high-level overview of the mission, summarising the surveycharacteristics, the various data-processing steps, and data products. We alsohighlight the main science objectives and expected performance