TY  - JOUR
A1  - Selsing, Jonatan
A1  - Malesani, D.
A1  - Goldoni, P.
A1  - Fynbo, Johan
A1  - Krühler, T.
A1  - Antonelli, L. A.
A1  - Arabsalmani, M.
A1  - Bolmer, J.
A1  - Cano, Z.
A1  - Christensen, L.
A1  - Covino, S.
A1  - De Cia, A.
A1  - de Ugarte Postigo, A.
A1  - Flores, H.
A1  - Fliis, M.
A1  - Gomboc, A.
A1  - Greiner, J.
A1  - Groot, P.
A1  - Hammer, F.
A1  - Hartoog, O. E.
A1  - Heintz, K. E.
A1  - Hjorth, J.
A1  - Jakobsson, P.
A1  - Japelj, J.
A1  - Kann, D. A.
A1  - Kaper, L.
A1  - Ledoux, C.
A1  - Leloudas, G.
A1  - Levan, A. J.
A1  - Maiorano, E.
A1  - Melandri, A.
A1  - Milvang-Jensen, B.
A1  - Palazzi, E.
A1  - Palmerio, J. T.
A1  - Perley, D. A.
A1  - Pian, E.
A1  - Piranomonte, S.
A1  - Pugliese, G.
A1  - Sanchez-Ramirez, R.
A1  - Savaglio, S.
A1  - Schady, P.
A1  - Schulze, S.
A1  - Sollerman, J.
A1  - Sparre, Martin
A1  - Tagliaferri, G.
A1  - Tanvir, N. R.
A1  - Thone, C. C.
A1  - Vergani, S. D.
A1  - Vreeswijk, P.
A1  - Watson, D.
A1  - Wiersema, K.
A1  - Wijers, R.
A1  - Xu, D.
A1  - Zafar, T.
T1  - The X-shooter GRB afterglow legacy sample (XS-GRB)
JF  - Astronomy and astrophysics : an international weekly journal
N2  - In this work we present spectra of all gamma-ray burst (GRB) afterglows that have been promptly observed with the X-shooter spectrograph until 31/03/2017. In total, we have obtained spectroscopic observations of 103 individual GRBs observed within 48 hours of the GRB trigger. Redshifts have been measured for 97 per cent of these, covering a redshift range from 0.059 to 7.84. Based on a set of observational selection criteria that minimise biases with regards to intrinsic properties of the GRBs, the follow-up effort has been focused on producing a homogeneously selected sample of 93 afterglow spectra for GRBs discovered by the Swift satellite. We here provide a public release of all the reduced spectra, including continuum estimates and telluric absorption corrections. For completeness, we also provide reductions for the 18 late-time observations of the underlying host galaxies. We provide an assessment of the degree of completeness with respect to the parent GRB population, in terms of the X-ray properties of the bursts in the sample and find that the sample presented here is representative of the full Swift sample. We have constrained the fraction of dark bursts to be <28 per cent and confirm previous results that higher optical darkness is correlated with increased X-ray absorption. For the 42 bursts for which it is possible, we have provided a measurement of the neutral hydrogen column density, increasing the total number of published HI column density measurements by similar to 33 per cent. This dataset provides a unique resource to study the ISM across cosmic time, from the local progenitor surroundings to the intervening Universe.
KW  - gamma-ray burst: general
KW  - galaxies: high-redshift
KW  - ISM: general
KW  - techniques: spectroscopic
KW  - catalogs
KW  - galaxies: star formation
Y1  - 2019
U6  - https://doi.org/10.1051/0004-6361/201832835
SN  - 1432-0746
SN  - 0004-6361
VL  - 623
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Bustamante, Sebastian
A1  - Sparre, Martin
A1  - Springel, Volker
A1  - Grand, Robert J. J.
T1  - Merger-induced metallicity dilution in cosmological galaxy formation simulations
JF  - Monthly notices of the Royal Astronomical Society
N2  - Observational studies have revealed that galaxy pairs tend to have lower gas-phase metallicity than isolated galaxies. This metallicity deficiency can be caused by inflows of low-metallicity gas due to the tidal forces and gravitational torques associated with galaxy mergers, diluting the metal content of the central region. In this work we demonstrate that such metallicity dilution occurs in state-of-the-art cosmological simulations of galaxy formation. We find that the dilution is typically 0.1 dex for major mergers, and is noticeable at projected separations smaller than 40 kpc. For minor mergers the metallicity dilution is still present, even though the amplitude is significantly smaller. Consistent with previous analysis of observed galaxies we find that mergers are outliers from the fundamental metallicity relation, with deviations being larger than expected for a Gaussian distribution of residuals. Our large sample of mergers within full cosmological simulations also makes it possible to estimate how the star formation rate enhancement and gas consumption timescale behave as a function of the merger mass ratio. We confirm that strong starbursts are likely to occur in major mergers, but they can also arise in minor mergers if more than two galaxies are participating in the interaction, a scenario that has largely been ignored in previous work based on idealised isolated merger simulations.
KW  - methods: numerical
KW  - galaxies: interactions
KW  - galaxies: star formation
KW  - galaxies: evolution
Y1  - 2018
U6  - https://doi.org/10.1093/mnras/sty1692
SN  - 0035-8711
SN  - 1365-2966
VL  - 479
IS  - 3
SP  - 3381
EP  - 3392
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Davidzon, Iary
A1  - Ilbert, Olivier
A1  - Faisst, Andreas L.
A1  - Sparre, Martin
A1  - Capak, Peter L.
T1  - An Alternate Approach to Measure Specific Star Formation Rates at 2 < z < 7
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We trace the specific star formation rate (sSFR) of massive star-forming galaxies (greater than or similar to 10(10)M(circle dot)) from z similar to 2 to 7. Our method is substantially different from previous analyses, as it does not rely on direct estimates of star formation rate, but on the differential evolution of the galaxy stellar mass function (SMF). We show the reliability of this approach by means of semianalytical and hydrodynamical cosmological simulations. We then apply it to real data, using the SMFs derived in the COSMOS and CANDELS fields. We find that the sSFR is proportional to (1 + z)(1.1) (+/-) (0.2) at z > 2, in agreement with other observations but in tension with the steeper evolution predicted by simulations from z similar to 4 to 2. We investigate the impact of several sources of observational bias, which, however, cannot account for this discrepancy. Although the SMF of high-redshift galaxies is still affected by significant errors, we show that future large-area surveys will substantially reduce them, making our method an effective tool to probe the massive end of the main sequence of star-forming galaxies.
KW  - galaxies: evolution
KW  - galaxies: high-redshift
KW  - galaxies: star formation
Y1  - 2018
U6  - https://doi.org/10.3847/1538-4357/aaa19e
SN  - 0004-637X
SN  - 1538-4357
VL  - 852
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Marino, Raffaella Anna
A1  - Cantalupo, Sebastiano
A1  - Lilly, Simon J.
A1  - Gallego, Sofia G.
A1  - Straka, Lorrie A.
A1  - Borisova, Elena
A1  - Pezzulli, Gabriele
A1  - Bacon, Roland
A1  - Brinchmann, Jarle
A1  - Carollo, C. Marcella
A1  - Caruana, Joseph
A1  - Conseil, Simon
A1  - Contini, Thierry
A1  - Diener, Catrina
A1  - Finley, Hayley
A1  - Inami, Hanae
A1  - Leclercq, Floriane
A1  - Muzahid, Sowgat
A1  - Richard, Johan
A1  - Schaye, Joop
A1  - Wendt, Martin
A1  - Wisotzki, Lutz
T1  - Dark Galaxy Candidates at Redshift similar to 3.5 Detected with MUSE
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - Recent theoretical models suggest that the early phase of galaxy formation could involve an epoch when galaxies are gas rich but inefficient at forming stars: a "dark galaxy" phase. Here, we report the results of our Multi-Unit Spectroscopic Explorer (MUSE) survey for dark galaxies fluorescently illuminated by quasars at z > 3. Compared to previous studies which are based on deep narrowband (NB) imaging, our integral field survey provides a nearly uniform sensitivity coverage over a large volume in redshift space around the quasars as well as full spectral information at each location. Thanks to these unique features, we are able to build control samples at large redshift distances from the quasars using the same data taken under the same conditions. By comparing the rest-frame equivalent width (EW0) distributions of the Ly alpha sources detected in proximity to the quasars and in control samples, we detect a clear correlation between the locations of high-EW0 objects and the quasars. This correlation is not seen in other properties, such as Ly alpha luminosities or volume overdensities, suggesting the possible fluorescent nature of at least some of these objects. Among these, we find six sources without continuum counterparts and EW0 limits larger than 240 angstrom that are the best candidates for dark galaxies in our survey at z > 3.5. The volume densities and properties, including inferred gas masses and star formation efficiencies, of these dark galaxy candidates are similar to those of previously detected candidates at z approximate to 2.4 in NB surveys. Moreover, if the most distant of these are fluorescently illuminated by the quasar, our results also provide a lower limit of t - 60 Myr on the quasar lifetime.
KW  - galaxies: formation
KW  - galaxies: high-redshift
KW  - galaxies: star formation
KW  - intergalactic medium
KW  - quasars: emission lines
KW  - quasars: general
Y1  - 2018
U6  - https://doi.org/10.3847/1538-4357/aab6aa
SN  - 0004-637X
SN  - 1538-4357
VL  - 859
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -