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We present an optical spectroscopic atlas for 123 core-dominated radio-loud active galactic nuclei with relativistic jets, drawn from the MOJAVE/2cm simple at 15 GHz. It is the first time that spectroscopic and photometric parameters for a large sample of such type of AGN are presented. The atlas includes spectral parameters for the emission lines Hβ, [O III] λ 5007, Mg II λ2798 and/or C IV λ1549 and corresponding data for the continuum, as well as the luminosities and equivalent widths of the Fe II UV/optical. It also contains homogeneous photometric information in the B-band for 242 sources of the sample, with a distribution peak at B J = 18.0 and a magnitude interval of 11.1 ≤ B J ≤ 23.7.
Presentamos un atlas espectroscópico óptico para 123 núcleos activos de galaxias compactos con la presencia de chorros superlumínicos, tomados de la muestra limitada en densidad de flujo a 15 GHz MOJAVE/2cm. Es la primera vez que se presentan los parámetros espectroscópicos y fotométricos para una muestra tan grande de este tipo de AGN. El atlas incluye los parámetros espectrales para las líneas de emisión Hβ, [O III]λ5007, Mg IIλ2798 y/ó C IVλ1549, junto con los datos para la emisión del continuo correspondiente. Se presentan además las luminosidades y el ancho equivalente del Fe II UV/óptico. Contiene también la información fotométrica homogénea en la banda B para 242 fuentes de la muestra, con un pico en la distribución de B J = 18.0 y un intervalo en magnitud de 11.1 ≤ B J ≤ 23.7.
We present the results of a long-term (1999–2010) spectral optical monitoring campaign of the active galactic nucleus (AGN) Ark 564, which shows a strong Fe ιι line emission in the optical. This AGN is a narrow-line Seyfert 1 (NLS1) galaxy, a group of AGNs with specific spectral characteristics. We analyze the light curves of the permitted Hα, Hβ, optical Fe ιι line fluxes, and the continuum flux in order to search for a time lag between them. Additionally, in order to estimate the contribution of iron lines from different multiplets, we fit the Hβ and Fe ιιlines with a sum of Gaussian components. We find that during the monitoring period the spectral variation (Fmax/Fmin) of Ark 564 is between 1.5 for Hα and 1.8 for the Fe ιιlines. The correlation between the Fe ιιand Hβ flux variations is of higher significance than that of Hα and Hβ (whose correlation is almost absent). The permitted-line profiles are Lorentzian-like and do not change shape during the monitoring period. We investigate, in detail, the optical Fe ιιemission and find different degrees of correlation between the Fe ιιemission arising from different spectral multiplets and the continuum flux. The relatively weak and different degrees of correlations between permitted lines and continuum fluxes indicate a rather complex source of ionization of the broad-line emission region.
Gglaxies: active Galaxies: individual (Ark 564) Galaxies: Seyfert– Line: profiles Quasars: emission lines CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA ASTRONOMÍA Y ASTROFÍSICA RADIOASTRONOMÍA PROPAGACIÓN DE ONDAS ELECTROMAGNÉTICAS PROPAGACIÓN DE ONDAS ELECTROMAGNÉTICAS
RAUL MUJICA GARCIA (2009)
We investigate the metallicity of the broad line region (BLR) of a sample of 30 quasars in the redshift range 4 < z < 6.4, by using near-IR and optical spectra. We focus on the ratio of the broad lines (SiIV1397+OIV]1402)/CIV1549, which is a good metallicity tracer of the BLR. We find that the metallicity of the BLR is very high even in QSOs at z∼6. The inferred metallicity of the BLR gas is so high (several times solar) that metal ejection or mixing with lower metallicity gas in the host galaxy is required to match the metallicities observed in local massive galaxies. On average, the observed metallicity changes neither among quasars in the observed redshift range 4 < z < 6.4, nor when compared with quasars at lower redshifts. We show that the apparent lack of metallicity evolution is a likely consequence of both the black hole-galaxy co-evolution and of selection effects. The data also suggest a lack of evolution in the carbon abundance, even among z > 6 quasars. The latter result is puzzling, since the minimum enrichment timescale of carbón is about 1 Gyr, i.e. longer than the age of the universe at z∼6.
Abundances Galaxies: abundances Galaxies: evolution Galaxies: high-redshift Quasars: emission lines CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA ASTRONOMÍA Y ASTROFÍSICA ASTRONOMÍA Y ASTROFÍSICA
Vahram Chavushyan (2012)
Since its launch in October 2002, the INTEGRAL satellite has revolutionized our knowledge of the hard X-ray sky thanks to its unprecedented imaging capabilities and source detection positional accuracy above 20 keV. Nevertheless, many of the newly-detected sources in the INTEGRAL sky surveys are of unknown nature. The combined use of available information at longer wavelengths (mainly soft X-rays and radio) and of optical spectroscopy on the putative counterparts of these new hard X-ray objects allows us to pinpoint their exact nature. Continuing our long-standing program that has been running since 2004, and using 6 different telescopes of various sizes together with data from an online spectroscopic survey, here we report the classification through optical spectroscopy of 22 more unidentified or poorly studied high-energy sources detected with the IBIS instrument onboard INTEGRAL.We found that 16 of them are active galactic nuclei (AGNs), while the remaining 6 objects are within our Galaxy. Among the identified extragalactic sources, the large majority (14) is made up of type 1 AGNs (i.e. with broad emission lines); of these, 6 lie at redshift larger than 0.5 and one (IGR J12319−0749) has z = 3.12, which makes it the second farthest object detected in the INTEGRAL surveys up to now. The remaining AGNs are of type 2 (that is, with narrow emission lines only), and one of the two cases is confirmed as a pair of interacting Seyfert 2 galaxies. The Galactic objects are identified as two cataclysmic variables, one high-mass X-ray binary, one symbiotic binary and two chromospherically active stars, possibly of RS CVn type. The main physical parameters of these hard X-ray sources were also determined using the multiwavelength information available in the literature. We thus still find that AGNs are the most abundant population among hard X-ray objects identified through optical spectroscopy. Moreover, we note that the higher sensitivity of the more recent INTEGRAL surveys is now enabling the detection of high-redshift AGNs, thus allowing the exploration of the most distant hard X-ray emitting sources and possibly of the most extreme blazars.
X-rays: binaries Galaxies: Seyfert X-rays: general Novae, cataclysmic variables Quasars: emission lines Stars: flare CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA ASTRONOMÍA Y ASTROFÍSICA ASTRONOMÍA Y ASTROFÍSICA
VAHRAM CHAVUSHYAN (2010)
Hard X–ray surveys performed by the INTEGRAL satellite have discovered a conspicuous fraction (up to 30%) of unidentified objects among the detected sources. Here we continue our program of identification of these objects by (i) selecting probable optical candidates by means of positional cross-correlation of the INTEGRAL detections with soft X–ray, radio, and/or optical archives and (ii) performing optical spectroscopy on them. As a result, we pinpointed and identified, or more accurately characterized, 44 definite or likely counterparts of INTEGRAL sources. Among them, 32 are active galactic nuclei (AGNs; 18 with broad emission lines, 13 with narrow emission lines only, and one X–ray bright, optically normal galaxy) with redshift 0.019 < z < 0.6058, 6 cataclysmic variables (CVs), 5 high-mass X–ray binaries (2 of which in the Small Magellanic Cloud), and 1 low-mass X–ray binary. This was achieved by using 7 telescopes of various sizes and archival data from two online spectroscopic surveys. The main physical parameters of these hard X–ray sources were also determined using the multiwavelength information available in the literature. In general, AGNs are the most abundant population among hard X–ray objects, and our results confirm the tendency of finding AGNs more frequently than any other type of hard X–ray emitting object among unidentified INTEGRAL sources when optical spectroscopy is used as an identification tool. Moreover, the deeper sensitivity of the more recent INTEGRAL surveys enables one to begin detecting hard X–ray emission above 20 keV from sources such as LINER-type AGNs and non-magnetic CVs.
Galaxies: Seyfert Quasars: emission lines X–rays: binaries Stars: novae, cataclysmic variables Techniques: spectroscopic X–rays: individuals CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA ASTRONOMÍA Y ASTROFÍSICA ASTRONOMÍA Y ASTROFÍSICA
VAHRAM CHAVUSHYAN (2009)
Within the framework of our program of assessment of the nature of unidentified or poorly known INTEGRAL sources, we present here spectroscopy of optical objects, selected through positional cross-correlation with soft X-ray detections (afforded with satellites such as Swift, ROSAT, Chandra and/or XMM-Newton) as putative counterparts of hard X-ray sources detected with the IBIS instrument onboard INTEGRAL. Using 6 telescopes of various sizes and archival data from two on-line spectroscopic surveys we are able to identify, either for the first time or independent of other groups, the nature of 20 INTEGRAL hard X-ray sources. Our results indicate that: 11 of these objects are active galactic nuclei (AGNs) at redshifts between 0.014 and 0.978, 7 of which display broad emission lines, 2 show narrow emission lines only, and 2 have unremarkable or no emission lines (thus are likely Compton thick AGNs); 5 are cataclysmic variables (CVs), 4 of which are (possibly magnetic) dwarf novae and one is a symbiotic star; and 4 are Galactic X-ray binaries (3 with high-mass companions and one with a low-mass secondary). It is thus again found that the majority of these sources are AGNs or magnetic CVs, confirming our previous findings. When possible, the main physical parameters for these hard X-ray sources are also computed using the multiwavelength information available in the literature. These identifications support the importance of INTEGRAL in the study of the hard X-ray spectrum of all classes of X-ray emitting objects, and the effectiveness of a strategy of multi-catalogue cross-correlation plus optical spectroscopy to securely pinpoint the actual nature of unidentified hard X-ray sources.
Galaxies: Seyfert Quasars: emission lines X-rays: binaries Stars: novae, cataclysmic variables Techniques: spectroscopic X-rays: general CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA ASTRONOMÍA Y ASTROFÍSICA ASTRONOMÍA Y ASTROFÍSICA
Andrew Humphrey (2011)
We have analysed the spatially integrated kinematic properties of the ionized gas within the inner r ≲ few kpc in 13 optically selected SDSS type 2 quasars at z ∼ 0.3–0.6, using the [O 🇮🇮🇮]λλ4959,5007 lines. The line profiles show a significant asymmetry in 11 objects. There is a clear preference for blue asymmetries, which are found in 9/13 quasars at 10 per cent intensity level. In coherence with studies on other types of active and non active galaxies, we propose that the asymmetries are produced by outflows where differential dust extinction is at work. This scenario is favoured by other results we find: in addition to quiescent ambient gas, whose kinematic properties are consistent with gravitational motions, we have discovered highly perturbed gas in all objects. This gas emits very broad lines (R = FWHM[O 🇮🇮🇮]/FWHMstars ≳2).While the quiescent gas shows small or null velocity shifts relative to the systemic velocity, the highly perturbed gas trends to show larger shifts which, moreover, are blueshifts in general. Within a given object, the most perturbed gas trends to have the largest blueshift as well. All together support that the perturbed gas, which is responsible for the blue asymmetries of the line profiles, is outflowing. The outflowing gas is located within the quasar ionization cones, in the narrow line region. The relative contribution of the outflowing gas to the total [O 🇮🇮🇮] line flux varies from object to object in the range ∼10–70 per cent. An anticorrelation is found such that, the more perturbed the outflowing gas is, the lower its relative contribution is to the total [O 🇮🇮🇮] flux. This suggests that outflows with more perturbed kinematics involve a smaller fraction of the total mass of ionized gas. Although some bias affects the sample, we argue that ionized gas outflows are a common phenomenon in optically selected type 2 quasars at 0.3≲ z ≲ 0.6.
Andrew Humphrey (2011)
We present long-slit spectroscopy and imaging data obtained with the Focal Reducer and Low Dispersion Spectrograph (FORS2) on the Very Large Telescope of 13 optically selected type 2 quasars at z ∼ 0.3–0.6 from the original sample of Zakamska et al. (2003). The sample is likely to be affected by different selection biases.We investigate the evidence for (i) mergers/interactions (ii) star formation activity in the neighbourhood of the quasars and (iii) extended emission-line regions (EELRs) and their nature. Evidence for mergers/interactions is found in 5/13 objects. This is a lower limit for our sample, given the shallowness ofmost of our continuum images. Although active galactic nucleus (AGN) photoionization cannot be totally discarded, line ratios consistent with stellar photoionization are found in general in companion galaxies/knots/nuclei near these same objects. On the contrary, the gas in the neighbourhood of the quasar nucleus shows line ratios inconsistent with HII galaxies and typical of AGN photoionized nebulae. A natural scenario to explain the observations is that star formation is ongoing in companion galaxies/knots/nuclei, possibly triggered by the interactions. These systems are, therefore, composite in their emission-line properties showing a combination of AGN and star formation features. EELRs have been found in 7/13 objects, although this fraction might be higher if a complete spatial coverage around the quasars was performed. The sizes vary between a few and up to 64 kpc. In general, the EELR apparently consists of an extended nebula associated with the quasar. In at least one case, the EELR is associated with ionized tidal features.
Andrew Humphrey (2011)
We present long-slit spectroscopy and imaging data obtained with the Focal Reducer and Low Dispersion Spectrograph (FORS2) on the Very Large Telescope of 13 optically selected type 2 quasars at z ∼ 0.3–0.6 from the original sample of Zakamska et al. (2003). The sample is likely to be affected by different selection biases.We investigate the evidence for (i) mergers/interactions (ii) star formation activity in the neighbourhood of the quasars and (iii)
extended emission-line regions (EELRs) and their nature. Evidence for mergers/interactions is found in 5/13 objects. This is a lower limit for our sample, given the shallowness ofmost of our continuum images. Although active galactic nucleus (AGN) photoionization cannot be totally discarded, line ratios consistent with stellar photoionization are found in general in companion galaxies/knots/nuclei near these same objects. On the contrary, the gas in the neighbourhood of the quasar nucleus shows line ratios inconsistent with HII galaxies and typical of AGN photoionized nebulae. A natural scenario to explain the observations is that star formation is ongoing in companion galaxies/knots/nuclei, possibly triggered by the interactions. These systems are, therefore, composite in their emission-line properties showing a combination of AGN and star formation features. EELRs have been found in 7/13 objects, although this fraction might be higher if a complete spatial coverage around the quasars was performed. The sizes vary between a few and up to 64 kpc. In general, the EELR apparently consists of an extended nebula associated with the quasar. In at least one case, the EELR is associated with ionized tidal features.
From a study of broad absorption line (BAL) + infrared (IR) + Fe 🇮🇮 quasi-stellar objects (QSOs) [using deep Gemini Multi-Object Spectrograph Integral Field Unit (GMOS-IFU) spectroscopy], new results are presented for IRAS 04505−2958. Specifically, we have studied in detail the outflow (OF) process at two large galactic scales: (i) two blobs/shells at radius r ∼ 1.1 and 2.2 kpc, and (ii) an external hypergiant shell at r ∼ 11 kpc. In addition, the presence of two very extended hypergiant shells at r ∼ 60–80 kpc is also discussed. From this GMOS study the following main results were obtained. (i) For the external hypergiant shell, the kinematics GMOS maps of the ionized gas ([O 🇮🇮], [Ne 🇮🇮🇮], [O 🇮🇮🇮], Hβ) show a small-scale bipolar OF, with similar properties to those observed in the prototype of exploding external supershells: NGC 5514. (ii) Three main knots – of this hypershell S3 –show the presence of a young starburst. (iii) The two internal shells show OF components with typical properties of nuclear shells. (iv) The two blobs and the hypershell are aligned at PA ∼131° showing bipolar OF shape at ∼10–15 kpc scale. In addition, the more external shells (at ∼60–80 kpc scale) are aligned at PA ∼ 40° also with bipolar OF shape (perpendicular to the more internal OF). (v) A strong blue continuum and multiple emission-line components were detected in all the GMOS fields. The new GMOS data show a good agreement with an extreme + explosive OF scenario for IRAS 04505−2958, in which part of the interstellar medium (ISM) of the host Galaxy was ejected (in multiple shells). This extreme OF could also be associated with two main processes in the evolution of QSOs: (i) the formation of companion/satellite galaxies by giant explosions; and (ii) to define the final mass of the host galaxy, and even if the explosive nuclear OF is extremely energetic, this process could disrupt an important fraction of the host galaxy. Finally, the generation of ultra-high-energy cosmic rays and neutrino/dark matter – associated with HyNe in explosive BAL + IR + Fe 🇮🇮 QSOs – is discussed.