75 research outputs found
QSO2 outflow characterization using data obtained with OSIRIS at the Gran Telescopio Canarias
Ionized outflows are ubiquitous in non radio-loud obscured quasars (QSO2s) at
different redshifts. We search for large-scale ionized outflows associated with
six optically selected QSO2 (five non-radio-loud and one radio-loud) at
0.2-0.5, targeting objects with extended radio structures. We have obtained
OSIRIS/GTC optical long slit spectroscopy data for these six QSO2 with the slit
located along the radio axis. We traced the gas kinematics with the
[OIII]4959,5007 lines to investigate ionized outflows and characterize
the dynamical state of the host galaxies. This second study has been
complemented with previously published FORS2/VLT spectroscopic data of 13 more
QSO2 at similar z. We identify ionized outflows in four out of the six QSO2
observed with the GTC. The outflows are spatially unresolved in two QSO2 and
compact in a third (radial size of R=0.80.3 kpc). Of particular interest
is the radio-quiet QSO2 SDSS 0741+3020 at z=0.47, associated with a giant
112 kpc nebula. An ionized outflow probably induced by the radio
structures has been detected along the axis defined by the central
1\arcsec\ radio structure, extending up to at least 4 kpc from the
active galactic nucleus (AGN). Turbulent gas (130 km s) has
also been detected across the giant gas nebula up to 40 kpc from the AGN.
This turbulence may have been induced by outflows triggered by the interaction
between a so-far undetected large-scale radio source and the nebula. Regarding
the dynamical state of the host galaxies, we find that the majority of the QSO2
show v/ 1, implying that they are dominated by random motions
(so-called dispersion-dominated systems). Most (17 of 19) fall in the area of
the E/S0 galaxies in the dynamical diagram v/ versus . None are
consistent with spiral or disk galaxies.Comment: 27 pages, 11+8 figures, accepted for publication in A&
Disc galaxy resolved in HI absorption against the radio lobe of 3C 433: Case study for future surveys
The neutral atomic gas content of galaxies is usually studied in the HI 21cm
emission line of hydrogen. However, at higher redshifts, we need very deep
integrations to detect HI emission. The HI absorption does not suffer from this
dependence on distance as long as there is a bright enough background radio
source. However, resolved HI absorption studies of galaxies are rare. We report
one such rare study of resolved HI absorption against the radio galaxy 3C 433
at with the VLA. The resolved kinematics of the absorber, located
against the southern lobe of the 3C 433, shows that it has regular kinematics
with an HI mass for T 100K.
Our deep optical continuum and H observations from the Gran Telescopio
CANARIAS (GTC) show that the absorber is a faint disc galaxy in the same
environment as 3C 433 with a stellar mass and a
star-formation rate of 0.15 or less. For its HI mass, HI
column density, stellar mass, and star-formation rate, this galaxy lies well
below the main sequence of star-forming galaxies. Its HI mass is lower than the
galaxies studied in HI emission at . Our GTC imaging reveals
interesting alignments between H and radio emission in the HI companion
and in the host galaxy of the AGN as well as in the circumgalactic medium in
between. This suggests that the shock ionization of gas by the propagating
radio source may happen across tens of kpc. Our work supports the potential of
studying the HI content in galaxies via absorption in the case of a fortuitous
alignment with an extended radio continuum. This allows us to trace galaxies
with low HI masses which would otherwise be missed by deep HI emission surveys.
In conjunction with the deep all-sky optical surveys, the blind HI surveys with
the SKA pathfinders will be able to detect many such systems.Comment: 11 pages, 9 figures. Accepted for publication in Astronomy &
Astrophysic
IAA : Información y actualidad astronómica (32)
Sumario :
El laboratorio de polvo cósmico del IAA ...2
La interminable historia del agua en la Luna ...6
Multiversos y cómics ...9
HISTORIAS DE ASTRONOMÍA. Caroline Herschel ...13
DECONSTRUCCIÓN Y otros ENSAYOS. Zoom al centro galáctico ...14
EL “MOBY DICK” DE... Marta González (IAA-CSIC)...16
ACTUALIDAD ...17
ENTRE BASTIDORES ...21
CIENCIA: PILARES E INCERTIDUMBRES
Tormentas solares ...22
ACTIVIDADES IAA, AGENDA Y RECOMENDADOS ...23 y 24N
IAA : Información y actualidad astronómica (36)
Sumario : Púlsares: faros para navegantes cósmicos.--
Espectroscopía: leyendo entre líneas (II).--
Un universo acelerado.--
CIENCIA EN HISTORIAS. Margaret Burbidge.--
DECONSTRUCCIÓN Y otros ENSAYOS. Hola, soy Nikola.--
EL “MOBY DICK” DE... Cristina Rodríguez López (IAA-CSIC).--
ACTUALIDAD.--
ENTRE BASTIDORES.--
SALA LIMPIA.--
CIENCIA: PILARES E INCERTIDUMBRES. La Vía Láctea.--
AGENDA/RECOMENDADOS.--N
Starburst radio galaxies: General properties, evolutionary histories and triggering
In this paper we discuss the results of a programme of spectral synthesis modelling of a sample of starburst radio galaxies in the context of scenarios for the triggering of the activity and the evolution of the host galaxies. New optical spectra are also presented for a subset of the objects discussed. The starburst radio galaxies - comprising ∼15-25 per cent of all powerful extragalactic radio sources - frequently show disturbed morphologies at optical wavelengths, and unusual radio structures, although their stellar masses are typical of radio galaxies as a class. In terms of the characteristic ages of their young stellar populations (YSPs), the objects can be divided into two groups: those with YSP ages tYSP≤ 0.1 Gyr, in which the radio source has been triggered quasi-simultaneously with the main starburst episode, and those with older YSP in which the radio source has been triggered or re-triggered a significant period after the starburst episode. Most of the former group are associated with a large mid- to far-IR (MFIR) continuum and [Oiii] emission-line luminosities (LIR > 1011L⊙, W), while most of the latter have lower luminosities. Combining the information on the YSP with that on the optical morphologies of the host galaxies, we deduce that the majority of the starburst radio galaxies have been triggered in galaxy mergers in which at least one of the galaxies is gas rich. However, the triggering (or re-triggering) of the radio jets can occur immediately before, around or a significant period after the final coalescence of the merging nuclei, reflecting the complex gas infall histories of the merger events. Although ∼25 per cent of starburst radio galaxies are sufficiently bright at MFIR wavelengths to be classified as ultraluminous infrared galaxies (ULIRGs), we show that only the most massive ULIRGs are capable of evolving into radio galaxies. Finally, for a small subset of starburst radio galaxies in rich clusters of galaxies, cooling flows associated with the hot X-ray haloes offer a viable alternative to mergers as a trigger for the radio jet activity. Overall, our results provide further evidence that a powerful radio jet activity can be triggered via a variety of mechanisms, including different evolutionary stages of major galaxy mergers; clearly, radio-loud AGN activity is not solely associated with a particular stage of a unique type of gas accretion event. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.This research has made use of the NASA/IPAC Extragalactic Data base (NED) which is operated by the Jet Propulsion Laboratory. Based on observations made with ESO Telescopes at the La Silla and Paranal observatories under programmes 70.B-0663(A), 71.B-0320(A), 078B-0660(A).Peer Reviewe
IAA : Información y actualidad astronómica (39)
Sumario : La evolución química del universo.--
Supervientos galácticos.--
CIENCIA EN HISTORIAS. Williamina Patton Fleming. De criada a
astrónoma.--
DECONSTRUCCIÓN Y otros ENSAYOS. El bosón de Higgs.--
EL “MOBY DICK” DE... Begoña Ascaso (IAA-CSIC).--
ACTUALIDAD.--
ENTRE BASTIDORES.--
SALA LIMPIA.--
CIENCIA: PILARES E INCERTIDUMBRES. Veinte años de cinturón
transneptuniano.N
IAA : Información y actualidad astronómica (26)
Sumario : Estrellas de neutrones: furioso magnetismo.--
La astronomía en el arte.--
DECONSTRUCCIÓN Y otros ENSAYOS :
Lo más frío del Universo.--
CIENCIA: PILARES E INCERTIDUMBRES :
Los meteoritos “ordinarios”.--
ACTUALIDAD.--
ENTRE BASTIDORES :
Las generaciones perdidas.--
HISTORIAS DE ASTRONOMÍA :
El organista que descubrió Urano.--
ACTIVIDADES IAA.Esta revista se publica con la ayuda FCT-08-0130 del Programa Nacional de Fomento de la Cultura Científica y Tecnológica 2008.N
IAA : Información y actualidad astronómica (12)
Sumario : INVESTIGACIÓN :
El misterioso arco de Lynx.--
Microlentes gravitatorias: lupas del Universo.--
VENTANA ABIERTA...hasta que la gorda cante.--
CHARLAS CON... Don Cox y Ron Reynolds.--
ACTUALIDAD CIENTÍFICA :
Explosiones en la superficie solar.--
La galaxia de Canis Major:
una bienvenida intrusa.--
Actividades IAA.--
Agenda.Esta revista se publica con la ayuda de la Acción Especial DIS 2003-10261-E del Programa Nacional de Difusión y divulgación de la Ciencia y la Tecnología, del Ministerio de Ciencia y Tecnología.N
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