J/A+A/629/A23 HLock01-LAB 2D spectrum (Marques-Chaves+, 2019)
Discovery of a giant and luminous Lyα+CIV+HeII nebula at z=3.326 with
extreme emission line ratios.
Marques-Chaves R., Perez-Fournon I., Villar-Martin M., Gavazzi R.,
Riechers D., Rigopoulou D., Wardlow J., Cabrera-Lavers A., Clements D.L.,
Colina L., Cooray A., Farrah D., Ivison R.J., Jimenez-Angel C.,
Martinez-Navajas P., Nayyeri H., Oliver S., Omont A., Scott D., Shu Y.
<Astron. Astrophys. 629, A23 (2019)>
=2019A&A...629A..23M 2019A&A...629A..23M (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Spectra, optical
Keywords: galaxies: formation - galaxies: high-redshift - ISM: general
Abstract:
We present the discovery of HLock01-LAB, a luminous and large
Lyα nebula at z=3.326. Medium-band imaging and long-slit
spectroscopic observations with the Gran Telescopio Canarias reveal
extended emission in the Lyα 1215Å, CIV 1550Å, and HeII
1640Å lines over ∼100kpc, and a total luminosity
L(Lyα)=(6.4±0.1)x1044erg/s. HLock01-LAB presents an
elongated morphology aligned with two faint radio sources contained
within the central ∼8kpc of the nebula. The radio structures are
consistent with faint radio jets or lobes of a central galaxy, whose
spectrum shows nebular emission characteristic of a type-II active
galactic nucleus (AGN). The continuum emission of the AGN at short
wavelengths is however likely dominated by stellar emission of the
host galaxy, for which we derive a stellar mass M*∼2.3x1011M☉.
Our kinematic analysis shows that the ionized gas is perturbed almost
exclusively in the inner region between the radio structures, probably
as a consequence of jet-gas interactions, whereas in the outer regions
the ionized gas appears more quiescent. The detection of extended
emission in CIV and CIII] indicates that the gas within the nebula is
not primordial. Feedback may have enriched the halo at at least 50kpc
from the nuclear region. Using rest-frame UV emission-line
diagnostics, we find that the gas in the nebula is likely heated by
the AGN. Nevertheless, at the center of the nebula we find extreme
emission line ratios of Lyα/CIV∼60 and Lyα/HeII∼80, one of
the highest values measured to date, and well above the standard
values of photoionization models (Lyα/HeII ∼30 for case B
photoionization). Our data suggest that jet-induced shocks are likely
responsible for the increase of the electron temperature and, thus,
the observed Lyα enhancement in the center of the nebula. This
scenario is further supported by the presence of radio structures and
perturbed kinematics in this region. The large Lyα luminosity in
HLock01-LAB is likely due to a combination of AGN photoionization and
jet-induced shocks, highlighting the diversity of sources of energy
powering Lyα nebulae. Future follow-up observations of
HLock01-LAB will help to reveal the finer details of the excitation
conditions of the gas induced by jets and to investigate the
underlying cooling and feedback processes in this unique object.
Description:
2D spectrum of HLock01-LAB from GTC/OSIRIS (R1000R grism). The
spectrum is wavelength and flux calibrated (units of Å and
erg/s/cm2/Å, respectively.). Each pixel has 0.254" and 2.589Å
in the spatial (XX) and spectral (YY) direction, respectively.
Objects:
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RA (2000) DE Designation(s)
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10 57 49.74 +57 30 15.0 HLock01-LAB
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 148 1 Information of fits 2D spectrum
fits/* . 1 fits 2D spectrum
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Right ascension (J2000)
4- 5 I2 min RAm Right ascension (J2000)
7- 11 F5.2 s RAs Right ascension (J2000)
12 A1 --- DE- Declination sign (J2000)
13- 14 I2 deg DEd Declination (J2000)
16- 17 I2 arcmin DEm Declination (J2000)
19- 22 F4.1 arcsec DEs Declination (J2000)
24- 26 I3 --- Nx Number of pixels along X-axis
28- 31 I4 --- Ny Number of pixels along Y-axis
33- 55 A23 "datime" Obs.date Observation date
57- 63 F7.2 0.1nm blambda Lower value of wavelength interval
65- 69 I5 0.1nm Blambda Upper value of wavelength interval
71- 77 F7.5 0.1nm dlambda Wavelength resolution
79- 82 I4 Kibyte size Size of FITS file
84-104 A21 --- FileName Name of FITS file, in subdirectory fits
106-148 A43 --- Title Title of the FITS file
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Acknowledgements:
Rui Marques-Chaves, rmarques(at)cab.inta-csic.es
(End) Rui Marques-Chaves [CAB, Spain], Patricia Vannier [CDS] 01-Aug-2019