Probing nuclear activity versus star formation at z ~ 0.8 using near-infrared multi-object spectroscopy
We present near-infrared (NIR) spectroscopic observations of 28 X-ray and mid-infrared selected sources at a median redshift of z ~ 0.8 in the Extended Groth Strip (EGS). To date this is the largest compilation ofNIR spectra of active galactic nuclei (AGN) at this redshift. The data were obtained us...
| Autores: | , , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2013 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/109673 |
| Acceso en línea: | http://hdl.handle.net/10261/109673 |
| Access Level: | acceso abierto |
| Palabra clave: | Galaxies: active Galaxies: nuclei Galaxies: star formation Infrared: galaxies |
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Probing nuclear activity versus star formation at z ~ 0.8 using near-infrared multi-object spectroscopyRodríguez-Espinosa, J. M.Acosta-Pulido, J. A.Alonso-Herrero, A.Pérez-García, Ana M.Rodríguez-Eugenio, N.Ramos-Almeida, CristinaGalaxies: activeGalaxies: nucleiGalaxies: star formationInfrared: galaxiesWe present near-infrared (NIR) spectroscopic observations of 28 X-ray and mid-infrared selected sources at a median redshift of z ~ 0.8 in the Extended Groth Strip (EGS). To date this is the largest compilation ofNIR spectra of active galactic nuclei (AGN) at this redshift. The data were obtained using the multi-object spectroscopic mode of the Long-slit Intermediate Resolution Infrared Spectrograph (LIRIS) at the 4.2 m William Herschel Telescope (WHT). These galaxies are representative of a larger sample studied in a previous work, consisting of over a hundred X-ray selected sources with mid-infrared counterparts, which were classified either as AGN dominated or host galaxy dominated, depending on the shape of their spectral energy distributions (SEDs). Here, we present new NIR spectra of 13 and 15 sources of each class, respectively. We detect the Hα line at ≥1.5σ above the continuum for the majority of the galaxies. Using attenuation-corrected Hα luminosities and observed Spitzer/MIPS 24 μm fluxes, and after subtracting an AGNcomponent estimated using an AGNempirical correlation and multifrequency SED fits, we obtain average star formation rates (SFRs) of 7 ± 7 and 20 ± 50 M⊙ yr-1, respectively (median SFRs = 7 and 5 M⊙ yr-1). These values are lower than the SFRs reported in the literature for different samples of non-active star-forming galaxies of similar stellar masses and redshifts (M*~1011M⊙ and z ~1). In spite of the small size of the sample studied here, as well as the uncertainty affecting the AGN-corrected SFRs, we speculate with the possibility of AGN quenching the star formation in galaxies at z~0.8. Alternatively, we might be seeing a delay between the offset of the star formation and AGN activity, as observed in the local Universe. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.The authors acknowledge the Spanish Ministry of Science and Innovation (MICINN) through project Consolider-Ingenio 2010 Programme grant CSD2006-00070: First Science with the GTC (http://www.iac.es/consolider-ingenio-gtc/). CRA acknowledges the Estallidos group through project PN AYA2010-21887-C04.04 and STFC PDRA (ST/G001758/1). AAH acknowledges support from the Spanish Plan Nacional de Astronomía y Astrofísica under grant AYA2009-05705-E and from the Universidad de Cantabria through the Augusto González Linares Programme. Funding for the DEEP2 survey has been provided by NSF grants AST95-09298, AST-0071048, AST-0071198, AST-0507428 and AST-0507483 as well as NASA LTSA grant NNG04GC89G.Peer ReviewedOxford University PressRoyal Astronomical SocietyMinisterio de Ciencia e Innovación (España)Ministerio de Economía y Competitividad (España)Universidad de CantabriaScience and Technology Facilities Council (UK)National Science Foundation (US)2015201520132015info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/109673reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttp://dx.doi.org/10.1093/mnras/sts611info:eu-repo/semantics/openAccessoai:digital.csic.es:10261/1096732026-05-22T06:33:51Z |
| dc.title.none.fl_str_mv |
Probing nuclear activity versus star formation at z ~ 0.8 using near-infrared multi-object spectroscopy |
| title |
Probing nuclear activity versus star formation at z ~ 0.8 using near-infrared multi-object spectroscopy |
| spellingShingle |
Probing nuclear activity versus star formation at z ~ 0.8 using near-infrared multi-object spectroscopy Rodríguez-Espinosa, J. M. Galaxies: active Galaxies: nuclei Galaxies: star formation Infrared: galaxies |
| title_short |
Probing nuclear activity versus star formation at z ~ 0.8 using near-infrared multi-object spectroscopy |
| title_full |
Probing nuclear activity versus star formation at z ~ 0.8 using near-infrared multi-object spectroscopy |
| title_fullStr |
Probing nuclear activity versus star formation at z ~ 0.8 using near-infrared multi-object spectroscopy |
| title_full_unstemmed |
Probing nuclear activity versus star formation at z ~ 0.8 using near-infrared multi-object spectroscopy |
| title_sort |
Probing nuclear activity versus star formation at z ~ 0.8 using near-infrared multi-object spectroscopy |
| dc.creator.none.fl_str_mv |
Rodríguez-Espinosa, J. M. Acosta-Pulido, J. A. Alonso-Herrero, A. Pérez-García, Ana M. Rodríguez-Eugenio, N. Ramos-Almeida, Cristina |
| author |
Rodríguez-Espinosa, J. M. |
| author_facet |
Rodríguez-Espinosa, J. M. Acosta-Pulido, J. A. Alonso-Herrero, A. Pérez-García, Ana M. Rodríguez-Eugenio, N. Ramos-Almeida, Cristina |
| author_role |
author |
| author2 |
Acosta-Pulido, J. A. Alonso-Herrero, A. Pérez-García, Ana M. Rodríguez-Eugenio, N. Ramos-Almeida, Cristina |
| author2_role |
author author author author author |
| dc.contributor.none.fl_str_mv |
Ministerio de Ciencia e Innovación (España) Ministerio de Economía y Competitividad (España) Universidad de Cantabria Science and Technology Facilities Council (UK) National Science Foundation (US) |
| dc.subject.none.fl_str_mv |
Galaxies: active Galaxies: nuclei Galaxies: star formation Infrared: galaxies |
| topic |
Galaxies: active Galaxies: nuclei Galaxies: star formation Infrared: galaxies |
| description |
We present near-infrared (NIR) spectroscopic observations of 28 X-ray and mid-infrared selected sources at a median redshift of z ~ 0.8 in the Extended Groth Strip (EGS). To date this is the largest compilation ofNIR spectra of active galactic nuclei (AGN) at this redshift. The data were obtained using the multi-object spectroscopic mode of the Long-slit Intermediate Resolution Infrared Spectrograph (LIRIS) at the 4.2 m William Herschel Telescope (WHT). These galaxies are representative of a larger sample studied in a previous work, consisting of over a hundred X-ray selected sources with mid-infrared counterparts, which were classified either as AGN dominated or host galaxy dominated, depending on the shape of their spectral energy distributions (SEDs). Here, we present new NIR spectra of 13 and 15 sources of each class, respectively. We detect the Hα line at ≥1.5σ above the continuum for the majority of the galaxies. Using attenuation-corrected Hα luminosities and observed Spitzer/MIPS 24 μm fluxes, and after subtracting an AGNcomponent estimated using an AGNempirical correlation and multifrequency SED fits, we obtain average star formation rates (SFRs) of 7 ± 7 and 20 ± 50 M⊙ yr-1, respectively (median SFRs = 7 and 5 M⊙ yr-1). These values are lower than the SFRs reported in the literature for different samples of non-active star-forming galaxies of similar stellar masses and redshifts (M*~1011M⊙ and z ~1). In spite of the small size of the sample studied here, as well as the uncertainty affecting the AGN-corrected SFRs, we speculate with the possibility of AGN quenching the star formation in galaxies at z~0.8. Alternatively, we might be seeing a delay between the offset of the star formation and AGN activity, as observed in the local Universe. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. |
| publishDate |
2013 |
| dc.date.none.fl_str_mv |
2013 2015 2015 2015 |
| dc.type.none.fl_str_mv |
info:eu-repo/semantics/article http://purl.org/coar/resource_type/c_6501 Publisher's version info:eu-repo/semantics/publishedVersion |
| format |
article |
| status_str |
publishedVersion |
| dc.identifier.none.fl_str_mv |
http://hdl.handle.net/10261/109673 |
| url |
http://hdl.handle.net/10261/109673 |
| dc.language.none.fl_str_mv |
Inglés |
| language_invalid_str_mv |
Inglés |
| dc.relation.none.fl_str_mv |
http://dx.doi.org/10.1093/mnras/sts611 |
| dc.rights.none.fl_str_mv |
info:eu-repo/semantics/openAccess |
| eu_rights_str_mv |
openAccess |
| dc.publisher.none.fl_str_mv |
Oxford University Press Royal Astronomical Society |
| publisher.none.fl_str_mv |
Oxford University Press Royal Astronomical Society |
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reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC instname:Consejo Superior de Investigaciones Científicas (CSIC) |
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Consejo Superior de Investigaciones Científicas (CSIC) |
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DIGITAL.CSIC. Repositorio Institucional del CSIC |
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DIGITAL.CSIC. Repositorio Institucional del CSIC |
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