The MUSE Hubble Ultra Deep Field Survey

Abstract

We present the MUSE Hubble Ultra Deep Survey, a mosaic of nine MUSE fields covering 90% of the entire HUDF region with a 10-h deep exposure time, plus a deeper 31-h exposure in a single 1.15 arcmin 2 field. The improved observing strategy and advanced data reduction results in datacubes with sub-arcsecond spatial resolution (0 . 65 at 7000 Å) and accurate astrometry (0 . 07 rms). We compare the broadband photometric properties of the datacubes to HST photometry, finding a good agreement in zeropoint up to m AB = 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 3σ 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 (m AB > 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 h 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 MUSEHubbleUltra Deep Field Survey

“…The data of the MUSE HUDF Survey were obtained as part of the MUSE GTO program (PI: R. Bacon). The MUSE HUDF Survey design is presented in Bacon et al (2017). It consists of two layers of different depths: the mosaic is composed of 9 MUSE pointings that cover a 3 × 3 area (9.92 arcmin 2 ) with an integration time of ≈ 10 hours; the udf-10 is a deeper integration at a 1 × 1 sub field within the mosaic, with an integration time of ≈ 31 hours.…”

“…The estimated 1 σ surface brightness limits are 2.8 × 10 −20 erg s −1 cm −2 Å −1 arcsec −2 and 5.5 × 10 −20 erg s −1 cm −2 Å −1 arcsec −2 in udf-10 and mosaic, respectively, in the wavelength range of 7000-8500 Å (excluding regions of OH sky emission, see Inami et al 2017, Bacon et al in prep. for more details). For instance, the estimated 3 σ flux limits are 1.5 × 10 −19 erg s −1 cm −2 and 3.1 × 10 −19 erg s −1 cm −2 in udf-10 and mosaic, respectively, for a point-like source extracted over three spectral channels (i.e., 3.75Å) around 7000 Å (see Figure 20 in Bacon et al 2017). The PSF and noise characteristics are similar to the DR1 data, except in the reddest part of the wavelength range.…”

“…Deep and homogeneous spectroscopic Lyα observations at a wide redshift range have been achieved in the Hubble Ultra Deep field (HUDF) by VLT/MUSE (Bacon et al 2010) in the guaranteed time observations (GTO), MUSE-HUDF survey (e.g. Bacon et al 2017). The LAE fraction has already been investigated with MUSE and HST data, using the MUSE-Wide GTO survey in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) Deep region in Caruana et al (2018).…”

Reconstruction of the ground-layer adaptive-optics point spread function for MUSE wide field mode observations

“…However, in some cases there are no bright point sources in the field of view because it is too small and/or is located at high galactic latitude where Galactic stars are rare. This is for example the case of deep-field observations like the Hubble Ultra Deep Field (UDF, Bacon et al 2017). A&A proofs: manuscript no.…”

The MUSE-Wide survey: A first catalogue of 831 emission line galaxies

“…Here we present results from the MUSE-Wide survey, a GTO programme complementing the ongoing ultra-deep pencil-beam MUSE surveys (Bacon et al 2017). MUSE-Wide trades depth for survey area by covering many fields with relatively shallow exposures (1 h per field).…”