Detalles de publicación
PP 021041
The OTELO survey: Revealing a population of low-luminosity current/active star-forming galaxies at z∼0.9
(1) ASPID, (2) Centro de Astrobiología (CSIC/INTA), (3) ISDEFE for European Space Astronomy Centre (ESAC)/ESA, (4) Departamento de Física de la Tierra y Astrofísica, Instituto de Física de Partículas y del Cosmos, Universidad Complutense de Madrid, (5) IRAM, (6) Geneva Observatory, (7) RAL Space, STFC Rutherford Appleton Laboratory, (8) ESAC,European Space Astronomy Center,
(9) IAC, (10) Departamento de Astrofísica ULL, (11) IAA, (12) Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, (13) Instituto de Astronomía, Universidad Nacional Autónoma de México,
(14) Instituto de Física de Cantabria, (15) Armagh Observatory and Planetarium,
(16) INAF, (17) Fundación Galileo Galilei
We use the red tunable filter of the instrument OSIRIS at GTC to obtain the pseudo spectra of emission line sources in the OTELO field. From these pseudo spectra we identify the objects with Hβ emission.
As the resolution of the pseudo spectra allows us to separate Hβ from [OIII], we are able to derive the Hβ flux without contamination from its adjacent line. Using data from the extended OTELO catalogue we discriminate AGNs and study the star formation rate, the stellar mass and the morphology of the star-forming galaxies.
We find that our sample is located on the main sequence of star-forming galaxies. The sources are morphologically classified mostly as disc-like galaxies (76%) and 90% of the sample as low-mass galaxies (M∗<1010M⊙). The low-mass star-forming galaxies at z∼0.9 detected by OTELO present similar properties to low-mass star-forming galaxies in the local universe, suggesting that this kind of object have not a favorite epoch of formation and star formation enhancement from z∼1 to now. Our sample of 40 Hβ star-forming galaxies includes the faintest Hβ emitters detected so far. This allows us to constrain the faint end of the luminosity function for the Hβ line alone with a minimum luminosity of logL=39ergs−1, a hundred times fainter than previous surveys. The dust-corrected OTELO Hβ luminosity function established the faint-end slope as α=−1.36±0.15. We increased the scope of the analysis to the bright end by adding ancillary data from the literature, non dust-corrected in this case. The obtained slope for this extended luminosity function is α=−1.43±0.12.
As the resolution of the pseudo spectra allows us to separate Hβ from [OIII], we are able to derive the Hβ flux without contamination from its adjacent line. Using data from the extended OTELO catalogue we discriminate AGNs and study the star formation rate, the stellar mass and the morphology of the star-forming galaxies.
We find that our sample is located on the main sequence of star-forming galaxies. The sources are morphologically classified mostly as disc-like galaxies (76%) and 90% of the sample as low-mass galaxies (M∗<1010M⊙). The low-mass star-forming galaxies at z∼0.9 detected by OTELO present similar properties to low-mass star-forming galaxies in the local universe, suggesting that this kind of object have not a favorite epoch of formation and star formation enhancement from z∼1 to now. Our sample of 40 Hβ star-forming galaxies includes the faintest Hβ emitters detected so far. This allows us to constrain the faint end of the luminosity function for the Hβ line alone with a minimum luminosity of logL=39ergs−1, a hundred times fainter than previous surveys. The dust-corrected OTELO Hβ luminosity function established the faint-end slope as α=−1.36±0.15. We increased the scope of the analysis to the bright end by adding ancillary data from the literature, non dust-corrected in this case. The obtained slope for this extended luminosity function is α=−1.43±0.12.