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J/A+A/610/A31       0.8-2.5um spectra of 2 red quasars              (Kim+, 2018)

What makes red quasars red? Observational evidence for dust extinction from line ratio analysis. Kim D., Im M. <Astron. Astrophys. 610, A31 (2018)> =2018A&A...610A..31K (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Spectra, infrared Keywords: quasars: general - quasars: emission lines - quasars: supermassive black holes - galaxies: evolution - galaxies: active Abstract: Red quasars are very red in the optical through near-infrared (NIR) wavelengths, which is possibly due to dust extinction in their host galaxies as expected in a scenario in which red quasars are an intermediate population between merger-driven star-forming galaxies and unobscured type 1 quasars. However, alternative mechanisms also exist to explain their red colors: (i) an intrinsically red continuum; (ii) an unusual high covering factor of the hot dust component, that is, CFHD=LHD/Lbol, where the LHD is the luminosity from the hot dust component and the Lbol is the bolometric luminosity; and (iii) a moderate viewing angle. In order to investigate why red quasars are red, we studied optical and NIR spectra of 20 red quasars at z∼0.3 and 0.7, where the usage of the NIR spectra allowed us to look into red quasar properties in ways that are little affected by dust extinction. The Paschen to Balmer line ratios were derived for 13 red quasars and the values were found to be ∼10 times higher than unobscured type 1 quasars, suggesting a heavy dust extinction with AV>2.5mag. Furthermore, the Paschen to Balmer line ratios of red quasars are difficult to explain with plausible physical conditions without adopting the concept of the dust extinction. The CFHD of red quasars are similar to, or marginally higher than, those of unobscured type 1 quasars. The Eddington ratios, computed for 19 out of 20 red quasars, are higher than those of unobscured type 1 quasars (by factors of 3-5), and hence the moderate viewing angle scenario is disfavored. Consequently, these results strongly suggest the dust extinction that is connected to an enhanced nuclear activity as the origin of the red color of red quasars, which is consistent with the merger-driven quasar evolution scenario. Description: We provide 0.8-2.5um spectra of two red quasars (0036-0113 and 1307+2338) taken with NASA IRTF. Objects: ------------------------------------------------------------------ RA (2000) DE Designation(s) (redshift) ------------------------------------------------------------------ 00 36 59.85 -01 13 32.30 0036-0113 (z=0.294) 13 07 00.62 +23 38 05.31 1307+2338 = F2MS J1307+2338 (z=0.275) ------------------------------------------------------------------ File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1a.dat 27 3032 0.8-2.5um spectrum of red quasar 0036-0113 tablea1b.dat 27 3037 0.8-2.5um spectrum of red quasar 1307+2338
See also: J/ApJ/812/66 : NIR spectra of 5 red quasars at 0.5<z<0.9 (Kim+, 2015) Byte-by-byte Description of file: tablea1a.dat tablea1b.dat
Bytes Format Units Label Explanations
1- 5 I5 0.1nm Wave Wavelength in Angstroms 7- 16 E10.4 10mW/m2/nm Flambda ?=- Flux in ergs/s/cm2/Angstrom 19- 27 E9.4 10mW/m2/nm e_Flambda ?=- Error in Flambda
Acknowledgements: Dohyeong Kim, dh.dr2kim(at)
(End) Patricia Vannier [CDS] 05-Mar-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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