J/A+A/628/A28 3C 294 NIR images and optical spectra (Heidt+, 2019)
3C 294 revisited: Deep Large Binocular Telescope AO NIR images and optical
spectroscopy.
Heidt J., Quirrenbach A., Hoyer N., Thompson D., Pramskiy A., Agapito G.,
Esposito S., Gredel R., Miller D., Pinna E., Puglisi A., Rossi F.,
Seifert W., Taylor G.
<Astron. Astrophys. 628, A28 (2019)>
=2019A&A...628A..28H 2019A&A...628A..28H (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Photometry ; Spectroscopy ; Redshifts
Keywords: instrumentation: adaptive optics - galaxies: active -
galaxies: high-redshift - quasars: emission lines -
quasars: individual: 3C 294
Abstract:
High redshift radio galaxies are among the most massive galaxies at
their redshift, are often found in the centers of proto-clusters of
galaxies, and are expected to evolve into the present day massive
central cluster galaxies. Thus they are a useful tool to explore
structure formation in the young Universe.
3C 294 is a powerful FR II type radio galaxy at z=1.786. Past
studies have identified a clumpy structure, possibly indicative of a
merging system, as well as tentative evidence that 3C 294 hosts a dual
AGN. Due to its proximity to a bright star, it was subject to various
adaptive optics imaging studies.
In order to distinguish between the various scenarios for 3C 294 we
performed deep high-resolution adaptive optics imaging and optical
spectroscopy of 3C 294 with the Large Binocular Telescope.
We resolve the 3C 294 system into three distinct components separated
by a few tenths of an arcsecond on our images. One is compact, the
other two are extended, all appear to be non-stellar. The nature of
each component is unclear. The latter could be a galaxy with an
internal absorption feature, a galaxy merger or two galaxies at
different redshifts. We can now uniquely associate the radio source of
3C 294 with one of the extended components. Based on our spectroscopy,
we determined a redshift of z=1.784±0.001, which is similar to the
one previously cited. In addition we found a previously unreported
emission line at lambda 6749.4Å in our spectra. It is not clear
that it originates from 3C 294. It could be the Ne [IV] doublet lambda
2424/2426Å at z=1.783, or belong to the compact component at a
redshift of z∼4.56. We thus can not unambiguously determine whether
3C 294 hosts a dual AGN or a projected pair of AGNs.
Description:
LUCI AO images in J, H, and Ks of 3C 294 as well as optical spectra of
3C 294 in the blue and red MODS channels are presented. The AO images
are from the two LBT mirrors combined as described in the paper at
PA=135. To preserve astrometry they are not rotated nor rebinned. The
spectra are given for each of the blue and red channel and are also
the spectra from both mirrors combined.
Objects:
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RA (2000) DE Designation(s)
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14 06 44.00 +34 11 25.0 3C 294 = NRAO 436
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 134 5 List of fits images and spectra
fits/* . 5 Individual fits images and spectra
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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- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny ? Number of pixels along Y-axis
30- 39 A10 "date" Obs.date Observation date
41- 47 F7.2 0.1nm blambda ? Lower value of wavelength interval for the
spectra
49- 56 F8.2 0.1nm Blambda ? upper value of wavelength interval for the
spectra
58- 61 I4 Kibyte size Size of FITS file
63- 74 A12 --- FileName Name of FITS file, in subdirectory fits
76-134 A59 --- Title Title of the FITS file
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Acknowledgements:
Jochen Heidt, jheidt(at)lsw.uni-heidelberg.de
(End) Jochen Heidt [LSW, Germany], Patricia Vannier [CDS] 02-Jul-2019