ePESSTO+ the advanced Public ESO Spectroscopic Survey of Transient Objects (PI: Inserra, ESO program IDs 1103.D-0328 and 106.216C) started in April 2019 and it is currently ongoing at the New Technology Telescope using the instruments EFOSC2 and SOFI. It is the second extension of the PESSTO survey (PI: Smartt).

ePESSTO+ targets supernovae and optical transients brighter than 20 mag for classification and selected science targets for detailed follow-up. It uses standard EFOSC2 setups with resolutions of 13-17Å between 3680-10320Å, SOFI spectroscopy for brighter science targets, with the blue and red (rarely) grisms (resolutions 23Å - 33Å), and SOFI imaging with broadband JHKs filters.

This first release includes spectra and images collected in the first 2.5 years of ePESSTO+ operations, from April 2019 to October 2021.

In this period spectra were taken for a total of 2138 objects; from that set, 178 ePESSTO+ Key Science targets were identified and followed-up for time series of EFOSC2 optical spectra, with the brighest also having SOFI spectra: 154 supernovae, 1 supernova imposter, 15 tidal disruption events (one of which is represented in the figure below), 2 LBV, 2 AGN, 4 supernova light echoes.

The higher resolution EFOSC grsims Gr#18 and Gr#20 were employed occasionally to allow higher spectral resolution for objects with H-Balmer lines in emission.

In total this release contains 14 GB of data: 2157 EFOSC2 spectra, 18 SOFI spectra, 480 SOFI images. The data products are available from the ESO Archive Science Portal or the Programmatic Access services, under the collection name ePESSTOplus, though the official name remains ePESSTO+.

More details about the release content can be found in the associated data release description.

The DOI assigned to the ePESSTO+ data collection is https://doi.org/10.18727/archive/86

Utilizing the UVES and GIRAFFE instruments, this comprehensive survey has encompassed all major components of the Milky Way, systematically studying 114,916 stars. The observed robust samples have enabled detailed observations of bulge, thick and thin disks, halo components, and open star clusters of various ages and Galactocentric distances.

UltraVISTA is an ultra-deep near-infrared survey of the central region of the COSMOS field. The fifth UltraVISTA data release comprises stacked images in YJHKs and NB118 narrow-band filters, as well as single-band and dual-mode source lists. The data release also contains a five-band merged catalogue, created from the individual Ks-selected source lists. The release is based on the observations carried out from December 2009 to mid 2019, corresponding to 81125 individual images. This is three years more than DR4. The additional data have almost homogenised the exposure time in the “deep” and “ultra-deep” stripes in the J, H and Ks filters, which now reach the same depths to ∼0.15 mag.

The release of the MUSE Hubble Ultra-Deep Field survey (Programmes 094.A-0289(B), 095.A-0010(A), 096.A-0045(A), 096.A-0045(B) and 1101.A-0127, PI R. Bacon) includes the deepest spectroscopic survey ever performed. The MUSE mosaic data cubes, with their 3D content, amazing depth, wide spectral range, and excellent spatial and medium spectral resolution, are rich in information. The 3σ point-source flux limit of an unresolved emission line reaches 3.1×10^-19 and 6.3×10^-20 erg s-1 cm^-2 at 10- and 141-hour depths, respectively. The redshifts of 2221 sources have securely been identified and measured. With the exception of eight stars, the collected sample consists of 25 nearby galaxies (z < 0.25), 677 [O ii] emitters (z = 0.25 - 1.5), 201 galaxies in the MUSE redshift desert range (z = 1.5 - 2.8) and 1308 Lyα emitters (z = 2.8 - 6.7). This represents an order of magnitude more than the collection of all spectroscopic redshifts obtained before MUSE in the Hubble ultra-deep field area (i.e., 2221 versus 292). At high redshift (z > 3), the difference is even more striking, with a factor of 65 increase (1308 versus 20).