Tol 2240–384 – a new low-metallicity AGN candidate
نویسندگان
چکیده
منابع مشابه
Emission-line Diagnostics of Low Metallicity AGN
Current emission-line based estimates of the metallicity of active galactic nuclei (AGN) at both high and low redshifts indicate that AGN have predominantly solar to supersolar metallicities. This leads to the question: do low metallicity AGN exist? In this paper we use photoionization models to examine the effects of metallicity variations on the narrow emission lines from an AGN. We explore a...
متن کاملNew beryllium observations in low-metallicity stars
We present observations of the Be II 313.0 nm resonance doublet in 14 halo and old disk stars with metallicities ranging from [Fe/H]=-0.4 to≈-3.0 obtained with the CASPEC spectrograph of the ESO 3.6m telescope at a FWHM≈ 8.6 kms−1 resolution. Abundances are derived bymeans of the synthetic spectra technique employing Kurucz (1993) atmospheric models, with enhanced α-elements and no overshooting...
متن کاملA Near-solar Metallicity Damped Lyman-α System toward the Bal Quasar Tol 1037−2703
We report the detection of a Broad Absorption Line (BAL) outflow in the spectrum of the zem (Mg ii) = 2.201 QSO Tol 1037−2703 with three main BALs at 36000, 25300 and 22300 km s outflow velocities. Although the overall flow is dominated by high ionization lines like N v and C iv , the gas of highest velocity shows absorption from Mg i, Mg ii and Fe ii. Covering factor arguments suggest that the...
متن کاملSdss J121811.0+465501.2: a New Low Surface Brightness Galaxy with Low Metallicity
We serendipitously find a new nearby Low Surface Brightness (LSB) galaxy from SDSS database. We estimate oxygen abundance of its H ii region SDSS J121811.0+465501.2 from electron temperature, as well as for another H ii region, SDSS J135440.5+535309.6, located in irregular LSB galaxy UGC8837. These two extragalactic H ii regions were classified as stars in the SDSS-DR4 database, and were found ...
متن کاملSpectroscopy Of Low Metallicity Giant H II Regions: A grid of low Metallicity Stellar atmospheres
We calculate a grid of spherically symmetric OB stellar atmospheres at low metallicities, including both non-local thermodynamic equilibrium (NLTE) and metal line blanketing effects. This is done to assess the uncertainties in helium abundance determination by nebular codes due to input stellar atmosphere models. The more sophisticated stellar atmosphere models we use can differ from LTE models...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Astronomy and Astrophysics
سال: 2010
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361/201014390