2007ApJS..173....1L


Query : 2007ApJS..173....1L

2007ApJS..173....1L - Astrophys. J., Suppl. Ser., 173, 1-36 (2007/November-0)

The intrinsically x-ray-weak quasar PHL 1811. II. Optical and UV spectra and Analysis.

LEIGHLY K.M., HALPERN J.P., JENKINS E.B. and CASEBEER D.

Abstract (from CDS):

This is the second of two papers reporting observations and analysis of the unusually bright (mb=14.4), luminous (MB=-25.5), nearby (z=0.192) narrow-line quasar PHL 1811. The first paper reported that PHL 1811 is intrinsically X-ray-weak and presented a spectral energy distribution (SED). Here we present HST STIS optical and UV spectra, and ground-based optical spectra. The optical and UV line emission is very unusual. There is no evidence for forbidden or semiforbidden lines. The near-UV spectrum is dominated by very strong Fe II and Fe III, and unusual low-ionization lines such as Na I D and Ca II H and K are observed. High-ionization lines are very weak; C IV has an equivalent width of 6.6 Å, a factor of ∼5 smaller than measured from quasar composite spectra. An unusual feature near 1200 Å can be deblended in terms of Lyα, N V, Si II, and C III* using the blueshifted C IV profile as a template. Photoionization modeling shows that the unusual line emission can be explained qualitatively by the unusually soft SED. Principally, a low gas temperature results in inefficient emission of collisionally excited lines, including the semiforbidden lines generally used as density diagnostics. The emission resembles that of high-density gas; in both cases this is a consequence of inefficient cooling. PHL 1811 is very unusual, but we note that quasar surveys may be biased against finding similar objects.

Abstract Copyright:

Journal keyword(s): Galaxies: Quasars: Emission Lines - quasars: individual (PHL 1811) - X-Rays: Galaxies

CDS comments: RX J2219.9-5941 is a misprint for RX J2217.9-5941, PHL 1181 is a misprint for PHL 1811.

Simbad objects: 23

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Number of rows : 23
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 Mrk 1502 Sy1 00 53 34.9326560879 +12 41 35.927159668   14.41 14.03     ~ 1075 1
2 2MASS J01341690-4258262 Sy1 01 34 16.9070384920 -42 58 26.220856306   18.17 17.30 16.71   ~ 69 0
3 2MASS J01395577+0619225 Sy1 01 39 55.7698488494 +06 19 22.518916337   16.80 17.00     ~ 161 0
4 QSO J0143-3917 QSO 01 43 33.6332299840 -39 17 00.065618732     16.28     ~ 25 0
5 QSO J0209-3939 QSO 02 09 28.6090162627 -39 39 38.953725898   17.35 17.15     ~ 65 0
6 LEDA 88588 Sy1 07 08 41.4887418009 -49 33 06.308287663   16.02 15.7 12.7   ~ 451 0
7 IRAS 07598+6508 Sy1 08 04 30.4643075056 +64 59 52.790728532   14.3 15.5     ~ 217 0
8 SDSS J094257.81-004705.1 BLL 09 42 57.8199188790 -00 47 05.211644506   19.30 18.88     ~ 27 0
9 Z 212-25 Sy1 10 34 38.5975589813 +39 38 28.181434249   17.37 16.90     ~ 322 1
10 [VV2006] J105023.7-010555 QSO 10 50 23.6877697408 -01 05 55.506709680   20.04 19.68     ~ 22 0
11 2MASS J12254197+2055033 Sy1 12 25 41.9501962377 +20 55 03.295974910   16.5       ~ 21 0
12 3C 273 BLL 12 29 06.6996828061 +02 03 08.598846466   13.05 14.830 14.11   ~ 5495 1
13 [VV2006] J130216.2+003031 QSO 13 02 16.1360187461 +00 30 32.142507976   23.63 22.10     ~ 36 0
14 LEDA 88835 Sy1 13 25 19.3805503234 -38 24 52.611897329   16.64 13.80 15.33   ~ 372 0
15 QSO J1409+2618 QSO 14 09 23.9086975485 +26 18 21.053512073   16.07 15.74     ~ 184 0
16 NGC 5548 Sy1 14 17 59.5401093128 +25 08 12.600227883   14.35 13.73     ~ 2496 0
17 [VV2006] J144231.7+011055 QSO 14 42 31.7221836498 +01 10 55.413109732   23.45 22.04     ~ 29 0
18 QSO J1532-0039 QSO 15 32 59.9565438130 -00 39 43.840064575   23.88 22.26     ~ 31 0
19 QSO J1546+5253 QSO 15 46 51.7542341944 +52 53 13.163859378   19.94 19.64     ~ 22 0
20 3C 351.0 Sy1 17 04 41.3742389551 +60 44 30.522600868   15.65 15.40 15.30   ~ 730 1
21 2QZ J215454.3-305654 BLL 21 54 54.3296382295 -30 56 53.391295865   19.55       ~ 18 0
22 PHL 1811 Sy1 21 55 01.5123415724 -09 22 24.351917710   13.9 16.8 14.1   ~ 166 1
23 2MASS J22175666-5941309 Sy1 22 17 56.6561264472 -59 41 30.817920584 16.30 17.08 16.78 16.80   ~ 41 0

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2021.12.06-19:33:44

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