Subaru Deep Spectroscopy of a Star-forming Companion Galaxy of BR 1202-0725 at $z=4.7$

Abstract

We present deep spatially-resolved optical spectroscopy of the NW companion galaxy of the quasar BR 1202-0725 at $z=4.7$. Its rest-frame UV spectrum shows star-forming activity in the nuclear region. The Ly$\alpha$ emission profile is symmetric with wavelength while its line width is unusually wide (FWHM $\simeq 1100$ km s${}^{-1}$) for such a high-$z$ star-forming galaxy. Spectrum taken along the Ly$\alpha$ nebula elongation, which is almost along the minor axis of the companion host galaxy, reveals that off-nuclear Ly$\alpha$ nebulae have either flat-topped or multi-peaked profiles along the extension. All these properties can be understood in terms of superwind activity in the companion galaxy. We also find a diffuse continuum component around the companion, which shows similar morphology to that of Ly$\alpha$ nebula, and is most likely due to scattering of the quasar light at dusty halo around the companion. We argue that the superwind could expel dusty material out to the halo region, making a dusty halo for scattering.

11 pages, 5 figures, to appear in AJ

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Cited by in corpus (16)

• Galactic Winds
• ALMA Observation of 158 micron [CII] Line and Dust Continuum of a z=7 Normally Star-forming Galaxy in the Epoch of Reionization
• A Detection of [CII] line emission in the z=4.7 QSO BR1202-0725
• The anatomy of an extreme starburst within 1.3Gyr of the Big Bang revealed by ALMA
• Varying [CII]/[NII] line ratios in the interacting system BR1202-0725 at z=4.7
• BR1202-0725: An Extreme Multiple Merger at z = 4.7
• Search for [CII] emission in z=6.5-11 star-forming galaxies
• A QSO host galaxy and its Lyalpha emission at z=6.43
• Spitzer Observations of High Redshift QSOs
• Close companions to two high-redshift quasars
• Herschel/PACS far-infrared photometry of two z>4 quasars
• Constraining the Nature of Two Ly-alpha Emitters detected by ALMA at z = 4.7
• The Ionised- and Cool-Gas Content of The BR1202-0725 System as seen by MUSE and ALMA
• Grisms Developed for FOCAS
• ALMA [NII] 205 micron Imaging Spectroscopy of the Interacting Galaxy System BRI 1202-0725 at Redshift 4.7
• K band SINFONI spectra of two $z\sim 5$ SMGs: upper limits to the un-obscured star formation from [O II] optical emission line searches