%0 Generic %1 vanzella2016highresolution %A Vanzella, E. %A De Barros, S. %A Cupani, G. %A Karman, W. %A Gronke, M. %A Balestra, I. %A Coe, D. %A Mignoli, M. %A Brusa, M. %A Calura, F. %A Caminha, G. B. %A Caputi, K. %A Castellano, M. %A Christensen, L. %A Comastri, A. %A Cristiani, S. %A Dijkstra, M. %A Fontana, A. %A Giallongo, E. %A Giavalisco, M. %A Gilli, R. %A Grazian, A. %A Grillo, C. %A Koekemoer, A. %A Meneghetti, M. %A Nonino, M. %A Pentericci, L. %A Rosati, P. %A Schaerer, D. %A Verhamme, A. %A Vignali, C. %A Zamorani, G. %D 2016 %K deep formation high-z spectroscopy star %T High-resolution spectroscopy at the faintest limits: an "ELT-like" spectrum of a young optically-thin L=0.02L* star-forming galaxy at z=3.12 %U http://arxiv.org/abs/1603.01616 %X We present VLT/X-Shooter and MUSE spectroscopy of an intrinsically faint F814W=28.82+/-0.33 (Muv=-16.8), low mass (<~10^7 Msol) and compact (R_eff=67pc) freshly star-forming galaxy at z=3.1169 magnified (20x) by the Hubble Frontier Fields galaxy cluster Abell S1063. Gravitational lensing allows for a significant jump toward low-luminosity regimes, in moderately high resolution spectroscopy (R=łambda/d ~ 3000-7400). In particular, we measured CIV1548-1550, HeII1640, OIII1661-1666, CIII1907-1909, Hb, OIII4959-5007, emission lines with FWHM<~50 km/s and (de-lensed) fluxes spanning the interval 1.0x10^(-19) - 2x10^(-18) erg/s/cm2 at S/N=4-30. The double peaked Lya emission with \Delta v(red-blue) = 280(+/-7)km/s and de-lensed fluxes 2_(blue)|7_(red)x10^(-18) erg/s/cm2 (S/N=38_(blue)|110_(red)) indicates a low column density of neutral hydrogen gas (N_HI~10^(16-18.5)cm^-2), consistent with an highly ionized interstellar medium as also inferred from the large OIII5007/OII3727>10 ratio. We detect CIV1548-1550 resonant doublet in emission, each component with FWHM <~ 45 km/s, and redshifted by +51(+/-10) km/s relative to the systemic redshift. We interpret this as nebular emission tracing an expanding optically-thin interstellar medium. Both CIV1548-1550 and HeII1640 suggest the presence of hot and massive stars (with a possible faint AGN). The ultraviolet slope is remarkably blue, =-2.95 (+/-0.20) (F_łambda=łambda^\beta), consistent with a dust-free and young <~20 Myr galaxy. We are witnessing an early episode of star-formation in which a relatively low N_HI and negligible dust attenuation might favor a leakage of ionizing radiation. This galaxy currently represents a unique low-luminosity reference object for future studies of the reionization epoch with JWST and ELT.

@misc{vanzella2016highresolution, abstract = {We present VLT/X-Shooter and MUSE spectroscopy of an intrinsically faint F814W=28.82+/-0.33 (Muv=-16.8), low mass (<~10^7 Msol) and compact (R_eff=67pc) freshly star-forming galaxy at z=3.1169 magnified (20x) by the Hubble Frontier Fields galaxy cluster Abell S1063. Gravitational lensing allows for a significant jump toward low-luminosity regimes, in moderately high resolution spectroscopy (R=\lambda/d \lambda ~ 3000-7400). In particular, we measured CIV1548-1550, HeII1640, OIII]1661-1666, CIII]1907-1909, Hb, [OIII]4959-5007, emission lines with FWHM<~50 km/s and (de-lensed) fluxes spanning the interval 1.0x10^(-19) - 2x10^(-18) erg/s/cm2 at S/N=4-30. The double peaked Lya emission with \Delta v(red-blue) = 280(+/-7)km/s and de-lensed fluxes 2_(blue)|7_(red)x10^(-18) erg/s/cm2 (S/N=38_(blue)|110_(red)) indicates a low column density of neutral hydrogen gas (N_HI~10^(16-18.5)cm^-2), consistent with an highly ionized interstellar medium as also inferred from the large [OIII]5007/[OII]3727>10 ratio. We detect CIV1548-1550 resonant doublet in emission, each component with FWHM <~ 45 km/s, and redshifted by +51(+/-10) km/s relative to the systemic redshift. We interpret this as nebular emission tracing an expanding optically-thin interstellar medium. Both CIV1548-1550 and HeII1640 suggest the presence of hot and massive stars (with a possible faint AGN). The ultraviolet slope is remarkably blue, \beta =-2.95 (+/-0.20) (F_\lambda=\lambda^\beta), consistent with a dust-free and young <~20 Myr galaxy. We are witnessing an early episode of star-formation in which a relatively low N_HI and negligible dust attenuation might favor a leakage of ionizing radiation. This galaxy currently represents a unique low-luminosity reference object for future studies of the reionization epoch with JWST and ELT.}, added-at = {2016-03-08T09:41:35.000+0100}, author = {Vanzella, E. and De Barros, S. and Cupani, G. and Karman, W. and Gronke, M. and Balestra, I. and Coe, D. and Mignoli, M. and Brusa, M. and Calura, F. and Caminha, G. B. and Caputi, K. and Castellano, M. and Christensen, L. and Comastri, A. and Cristiani, S. and Dijkstra, M. and Fontana, A. and Giallongo, E. and Giavalisco, M. and Gilli, R. and Grazian, A. and Grillo, C. and Koekemoer, A. and Meneghetti, M. and Nonino, M. and Pentericci, L. and Rosati, P. and Schaerer, D. and Verhamme, A. and Vignali, C. and Zamorani, G.}, biburl = {https://www.bibsonomy.org/bibtex/2966a6c96629ed7258953741bfa4d7620/miki}, description = {[1603.01616] High-resolution spectroscopy at the faintest limits: an "ELT-like" spectrum of a young optically-thin L=0.02L* star-forming galaxy at z=3.12}, interhash = {d5b2244d0d863e4b93a80a4ab1412f6e}, intrahash = {966a6c96629ed7258953741bfa4d7620}, keywords = {deep formation high-z spectroscopy star}, note = {cite arxiv:1603.01616Comment: 7 pages, 4 figures and 1 table; ApJL submitted}, timestamp = {2016-03-08T09:41:35.000+0100}, title = {High-resolution spectroscopy at the faintest limits: an "ELT-like" spectrum of a young optically-thin L=0.02L* star-forming galaxy at z=3.12}, url = {http://arxiv.org/abs/1603.01616}, year = 2016 }