slideshow 0 slideshow 0 slideshow 0 slideshow 0 slideshow 0 slideshow 0 slideshow 0 slideshow 0 slideshow 0 slideshow 0 slideshow 0 slideshow 0 slideshow 0 slideshow 0 slideshow 0 slideshow 0

THE MASS-METALLICITY AND FUNDAMENTAL METALLICITY RELATIONS AT z > 2 USING VERY LARGE TELESCOPE AND SUBARU NEAR-INFRARED SPECTROSCOPY OF zCOSMOS GALAXIES

Titulo: 
THE MASS-METALLICITY AND FUNDAMENTAL METALLICITY RELATIONS AT z > 2 USING VERY LARGE TELESCOPE AND SUBARU NEAR-INFRARED SPECTROSCOPY OF zCOSMOS GALAXIES
Autores: 
Maier, C; Lilly, SJ; Ziegler, BL; Contini, T; Montero, EP; Peng, Y; Balestra, I
Resumen: 
In the local universe, there is good evidence that, at a given stellar mass M, the gas-phase metallicity Z is anti-correlated with the star formation rate (SFR) of the galaxies. It has also been claimed that the resulting Z(M, SFR) relation is invariant with redshift-the so-called 'fundamental metallicity relation' (FMR). Given a number of difficulties in determining metallicities, especially at higher redshifts, the form of the Z(M, SFR) relation and whether it is really independent of redshift is still very controversial. To explore this issue at z > 2, we used VLT-SINFONI and Subaru-MOIRCS near-infrared spectroscopy of 20 zCOSMOS-deep galaxies at 2.1 < z < 2.5 to measure the strengths of up to five emission lines: [O II]lambda 3727, H beta, [O III]lambda 5007, H alpha, and [N II]lambda 6584. This near-infrared spectroscopy enables us to derive O/H metallicities, and also SFRs from extinction corrected H alpha measurements. We find that the mass-metallicity relation (MZR) of these star-forming galaxies at z approximate to 2.3 is lower than the local Sloan Digital Sky Survey (SDSS) MZR by a factor of three to five, a larger change than found by Erb et al. using [N II]/H alpha-based metallicities from stacked spectra. We discuss how the different selections of the samples and metallicity calibrations used may be responsible for this discrepancy. The galaxies show direct evidence that the SFR is still a second parameter in the MZR at these redshifts. However, determining whether the Z(M, SFR) relation is invariant with epoch depends on the choice of extrapolation used from local samples, because z > 2 galaxies of a given mass have much higher SFRs than the local SDSS galaxies. We find that the zCOSMOS galaxies are consistent with a non-evolving FMR if we use the physically motivated formulation of the Z(M, SFR) relation from Lilly et al., but not if we use the empirical formulation of Mannucci et al.
Autor principal: 
Maier, C
Autor/es del IAA: 
Montero, E. Perez
DOI: 
10.1088/0004-637X/792/1/3
Revista: 
ASTROPHYSICAL JOURNAL
Fecha de publicación: 
2014/09/01
Volumen: 
792
Issue: 
1
Tipo de documento: 
Article
Palabras clave: 
galaxies: evolution; galaxies: high-redshift; ISM: abundances
Número de artículo: 
3

CONSTRAINTS ON THE PROGENITOR SYSTEM AND THE ENVIRONS OF SN 2014J FROM DEEP RADIO OBSERVATIONS

Titulo: 
CONSTRAINTS ON THE PROGENITOR SYSTEM AND THE ENVIRONS OF SN 2014J FROM DEEP RADIO OBSERVATIONS
Autores: 
Perez-Torres, MA; Lundqvist, P; Beswick, RJ; Bjornsson, CI; Muxlow, TWB; Paragi, Z; Ryder, S; Alberdi, A; Fransson, C; Marcaide, JM; Marti-Vidal, I; Ros, E; Argo, MK; Guirado, JC
Resumen: 
We report deep EVN and eMERLIN observations of the Type Ia SN 2014J in the nearby galaxy M82. Our observations represent, together with JVLA observations of SNe 2011fe and 2014J, the most sensitive radio studies of Type Ia SNe ever. By combining data and a proper modeling of the radio emission, we constrain the mass-loss rate from the progenitor system of SN 2014J to (M) over dot less than or similar to 7.0 x 10(-10) M yr(-1) (for a wind speed of 100 km s(-1)). If the medium around the supernova is uniform, then n(ISM) less than or similar to 1.3 cm(-3), which is the most stringent limit for the (uniform) density around a Type Ia SN. Our deep upper limits favor a double-degenerate (DD) scenario-involving two WD stars-for the progenitor system of SN 2014J, as such systems have less circumstellar gas than our upper limits. By contrast, most single-degenerate (SD) scenarios, i.e., the wide family of progenitor systems where a red giant, main-sequence, or sub-giant star donates mass to an exploding WD, are ruled out by our observations. (While completing our work, we noticed that a paper by Margutti et al. was submitted to The Astrophysical Journal. From a non-detection of X-ray emission from SN 2014J, the authors obtain limits of (M) over dot less than or similar to 1.2 x 10(-9) M-circle dot yr(-1) (for a wind speed of 100 km s(-1)) and n(ISM) less than or similar to 3.5 cm(-3), for the rho proportional to r(-2) wind and constant density cases, respectively. As these limits are less constraining than ours, the findings by Margutti et al. do not alter our conclusions. The X-ray results are, however, important to rule out free-free and synchrotron self-absorption as a reason for the radio non-detections.) Our estimates on the limits on the gas density surrounding SN2011fe, using the flux density limits from Chomiuk et al., agree well with their results. Although we discuss the possibilities of an SD scenario passing observational tests, as well as uncertainties in the modeling of the radio emission, the evidence from SNe 2011fe and 2014J points in the direction of a DD scenario for both.
Autor principal: 
Perez-Torres, MA
Autor/es del IAA: 
Perez-Torres, M. A.; Alberdi, A.
DOI: 
10.1088/0004-637X/792/1/38
Revista: 
ASTROPHYSICAL JOURNAL
Fecha de publicación: 
2014/09/01
Volumen: 
792
Issue: 
1
Tipo de documento: 
Article
Palabras clave: 
stars: mass-loss; Supernovae: individual (SN2011fe, SN2014J)
Número de artículo: 
38

IMAGING THE INNER AND OUTER GAPS OF THE PRE-TRANSITIONAL DISK OF HD 169142 AT 7 mm

Titulo: 
IMAGING THE INNER AND OUTER GAPS OF THE PRE-TRANSITIONAL DISK OF HD 169142 AT 7 mm
Autores: 
Osorio, M; Anglada, G; Carrasco-Gonzalez, C; Torrelles, JM; Macias, E; Rodriguez, LF; Gomez, JF; D'Alessio, P; Calvet, N; Nagel, E; Dent, WRF; Quanz, SP; Reggiani, M; Mayen-Gijon, JM
Resumen: 
We present Very Large Array observations at 7 mm that trace the thermal emission of large dust grains in the HD 169142 protoplanetary disk. Our images show a ring of enhanced emission of radius similar to 25-30 AU, whose inner region is devoid of detectable 7 mm emission. We interpret this ring as tracing the rim of an inner cavity or gap, possibly created by a planet or a substellar companion. The ring appears asymmetric, with the western part significantly brighter than the eastern one. This azimuthal asymmetry is reminiscent of the lopsided structures that are expected to be produced as a consequence of trapping of large dust grains. Our observations also reveal an outer annular gap at radii from similar to 40 to similar to 70 AU. Unlike other sources, the radii of the inner cavity, the ring, and the outer gap observed in the 7 mm images, which trace preferentially the distribution of large (millimeter/centimeter sized) dust grains, coincide with those obtained from a previous near-infrared polarimetric image, which traces scattered light from small (micron-sized) dust grains. We model the broadband spectral energy distribution and the 7 mm images to constrain the disk physical structure. From this modeling we infer the presence of a small (radius similar to 0.6 AU) residual disk inside the central cavity, indicating that the HD 169142 disk is a pre-transitional disk. The distribution of dust in three annuli with gaps in between them suggests that the disk in HD 169142 is being disrupted by at least two planets or substellar objects.
Autor principal: 
Osorio, M
Autor/es del IAA: 
Osorio, Mayra; Anglada, Guillem; Macias, Enrique; Gomez, Jose F.; Mayen-Gijon, Juan M.
DOI: 
10.1088/2041-8205/791/2/L36
Revista: 
ASTROPHYSICAL JOURNAL LETTERS
Fecha de publicación: 
2014/08/20
Volumen: 
791
Issue: 
2
Tipo de documento: 
Article
Palabras clave: 
planet-disk interactions; protoplanetary disks; stars: formation; stars: individual (HD 169142); stars: pre-main sequence
Número de artículo: 
L36

INSIGHTS ON THE STELLAR MASS-METALLICITY RELATION FROM THE CALIFA SURVEY

Titulo: 
INSIGHTS ON THE STELLAR MASS-METALLICITY RELATION FROM THE CALIFA SURVEY
Autores: 
Delgado, RMG; Fernandes, RC; Garcia-Benito, R; Perez, E; de Amorim, AL; Cortijo-Ferrero, C; Lacerda, EAD; Fernandez, RL; Sanchez, SF; Asari, NV; Alves, J; Bland-Hawthorn, J; Galbany, L; Gallazzi, A; Husemann, B; Bekeraite, S; Jungwiert, B; Lopez-Sanchez, AR; de Lorenzo-Caceres, A; Marino, RA; Mast, D; Molla, M; del Olmo, A; Sanchez-Blazquez, P; van de Ven, G; Vilchez, JM; Walcher, CJ; Wisotzki, L; Ziegler, B
Resumen: 
We use spatially and temporally resolved maps of stellar population properties of 300 galaxies from the CALIFA integral field survey to investigate how the stellar metallicity (Z(star)) relates to the total stellar mass (M-star) and the local mass surface density (mu(star)) in both spheroidal-and disk-dominated galaxies. The galaxies are shown to follow a clear stellar mass-metallicity relation (MZR) over the whole 10(9)-10(12) M-circle dot range. This relation is steeper than the one derived from nebular abundances, which is similar to the flatter stellar MZR derived when we consider only young stars. We also find a strong relation between the local values of mu(star) and Z(star) (the mu ZR), betraying the influence of local factors in determining Z(star). This shows that both local (mu(star)-driven) and global (M-star-driven) processes are important in determining metallicity in galaxies. We find that the overall balance between local and global effects varies with the location within a galaxy. In disks, mu(star) regulates Z(star), producing a strong mu ZR whose amplitude is modulated by M-star. In spheroids it is M-star that dominates the physics of star formation and chemical enrichment, with mu(star) playing a minor, secondary role. These findings agree with our previous analysis of the star formation histories of CALIFA galaxies, which showed that mean stellar ages are mainly governed by surface density in galaxy disks and by total mass in spheroids.
Autor principal: 
Delgado, RMG
Autor/es del IAA: 
Gonzalez Delgado, R. M.; Garcia-Benito, R.; Perez, E.; Cortijo-Ferrero, C.; Lopez Fernandez, R.; Sanchez, S. F.; del Olmo, A.; Vilchez, J. M.
DOI: 
10.1088/2041-8205/791/1/L16
Revista: 
ASTROPHYSICAL JOURNAL LETTERS
Fecha de publicación: 
2014/08/10
Volumen: 
791
Issue: 
1
Tipo de documento: 
Article
Palabras clave: 
galaxies: evolution; galaxies: fundamental parameters; galaxies: stellar content; galaxies: structure
Número de artículo: 
L16

Analogue transformation acoustics and the compression of spacetime

Titulo: 
Analogue transformation acoustics and the compression of spacetime
Autores: 
Garcia-Meca, C; Carloni, S; Barcelo, C; Jannes, G; Sanchez-Dehesa, J; Martinez, A
Resumen: 
A recently developed technique known as analogue transformation acoustics has allowed the extension of the transformational paradigm to general spacetime transformations under which the acoustic equations are not form invariant. In this paper, we review the fundamentals of analogue transformation acoustics and show how this technique can be applied to build a device that increases the density of events within a given spacetime region by simultaneously compressing space and time. (C) 2014 Elsevier B.V. All rights reserved.
Autor principal: 
Garcia-Meca, C
Autor/es del IAA: 
Barcelo, Carlos
DOI: 
10.1016/j.photonics.2014.05.001
Revista: 
PHOTONICS AND NANOSTRUCTURES-FUNDAMENTALS AND APPLICATIONS
Fecha de publicación: 
2014/08
Volumen: 
12
Issue: 
4
Páginas: 
312-318
Tipo de documento: 
Article
Palabras clave: 
Metamaterials; Transformation acoustics; Analogue gravity; Spacetime; Compressor

Transformational acoustic metamaterials based on pressure gradients

Titulo: 
Transformational acoustic metamaterials based on pressure gradients
Autores: 
Garcia-Meca, C; Carloni, S; Barcelo, C; Jannes, G; Sanchez-Dehesa, J; Martinez, A
Resumen: 
We apply a homogenization process to the acoustic velocity potential wave equation. The study of various examples shows that the resulting effective properties are different from those of the homogenized pressure wave equation for the same underlying acoustic parameters. A careful analysis reveals that a given set of inhomogeneous parameters represents an entirely different physical system depending on the considered equation. Our findings unveil a different way of tailoring acoustic properties through gradients of the static pressure. In contrast to standard metafluids based on isobaric composites, this alternative kind of metafluid is suitable for the implementation of transformational devices designed via the velocity potential equation. This includes acoustic systems in a moving background or arising from general space-time transformations. As an example, we design a device able to cloak the acoustic velocity potential.
Autor principal: 
Garcia-Meca, C
Autor/es del IAA: 
Barcelo, C.
DOI: 
10.1103/PhysRevB.90.024310
Revista: 
PHYSICAL REVIEW B
Fecha de publicación: 
2014/07/31
Volumen: 
90
Issue: 
2
Tipo de documento: 
Article
Número de artículo: 
024310

Three-dimensional Martian ionosphere model: II. Effect of transport processes due to pressure gradients

Titulo: 
Three-dimensional Martian ionosphere model: II. Effect of transport processes due to pressure gradients
Autores: 
Chaufray, JY; Gonzalez-Galindo, F; Forget, F; Lopez-Valverde, M; Leblanc, F; Modolo, R; Hess, S; Yagi, M; Blelly, PL; Witasse, O
Resumen: 
To study the transport of the ionospheric plasma on Mars, we have included a 3-D multifluid dynamical core in a Martian general circulation model. Vertical transport modifies the ion density above similar to 160 km on the dayside, especially the ions produced at high altitudes like O+, N+, and C+. Near the exobase, the dayside to nightside flow velocity reaches few hundreds of m/s, due to a large horizontal pressure gradient. Comparison with Mars Express/Analyzer of Space Plasmas and Energetic Atoms-3 measurements between 290 and 500 km suggests that this flow could account for at least 20% of the flow produced by the solar wind. This flow is not sufficient to populate substantially the nightside ionosphere at high altitudes, in agreement with recent observations, because of a strong nightside downward flow produced by vertical pressure gradient. The O-2(+) and NO+ ion densities on the nightside at low altitudes (similar to 130 km) are modified by this downward flow, compared to simulated densities without ion dynamics, while other ions are lost by chemical reactions. Variability at different time scales (diurnal, seasonal, and solar cycles) are studied. We simulate diurnal and seasonal variations of the ionospheric composition due to the variability of the neutral atmosphere and solar flux at the top of the atmosphere. The ionospheric dynamics are not strongly affected by seasons and solar cycles, and the retroaction of the ionosphere on the neutral atmosphere temperature and velocity is negligible compared to other physical processes below the exobase.
Autor principal: 
Chaufray, JY
Autor/es del IAA: 
Gonzalez-Galindo, F.; Lopez-Valverde, M.
DOI: 
10.1002/2013JE004551
Revista: 
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
Fecha de publicación: 
2014/07
Volumen: 
119
Issue: 
7
Páginas: 
1614-1636
Tipo de documento: 
Article

Quasars and their emission lines as cosmological probes

Titulo: 
Quasars and their emission lines as cosmological probes
Autores: 
Marziani, P; Sulentic, JW
Resumen: 
Quasars are the most luminous sources in the Universe. They are currently observed out to redshift z approximate to 7 when the Universe was less than one tenth of its present age. Since their discovery 50 years ago astronomers have dreamed of using them as standard candles. Unfortunately quasars cover a very large range (8 dex) of luminosity making them far from standard. We briefly review several methods that can potentially exploit quasars properties and allow us to obtain useful constraints on principal cosmological parameters. Using our 4D Eigenvector 1 formalism we have found a way to effectively isolate quasars radiating near the Eddington limit. If the Eddington ratio is known, under several assumptions it is possible to derive distance independent luminosities. We discuss the main statistical and systematic errors involved, and whether these 'standard Eddington candles' can be actually used to constrain cosmological models. (C) 2013 COSPAR. Published by Elsevier Ltd. All rights reserved.
Autor principal: 
Marziani, P
Autor/es del IAA: 
Sulentic, Jack W.
DOI: 
10.1016/j.asr.2013.10.007
Revista: 
ADVANCES IN SPACE RESEARCH
Fecha de publicación: 
2014/10/01
Volumen: 
54
Issue: 
7
Páginas: 
1331-1340
Tipo de documento: 
Article; Proceedings Paper
Palabras clave: 
Cosmological parameters; Emission lines; Quasars: general

A photoionization method for estimating BLR 'size' in quasars

Titulo: 
A photoionization method for estimating BLR 'size' in quasars
Autores: 
Negrete, CA; Dultzin, D; Marziani, P; Sulentic, JW
Resumen: 
We describe an alternate way to estimate Broad Line Region (BLR) radii for type-1 AGN based on determination of physical conditions in the BLR under the assumption that the line emitting gas is photoionized by a central continuum source. We derive 'diagnostic' intensity ratios involving UV lines AlIII lambda 1860, SiIII]lambda 1892 and CIV lambda 1549 which enable us to compute the ionizing photon flux, and hence BLR radius from the ionization parameter definition. We compare our estimates of BLR radii with values independently obtained from reverberation monitoring of H beta and, in a few cases, of C IV lambda 1549. We analyze the interpretation of the photoionization estimates in the 4D eigenvector 1 context, and discuss in some detail the case of 3C 390.3. For this object we are able to provide not only the ionizing photon flux, but also an estimate of density and ionization parameter from the measured diagnostic ratios. We also compare black hole masses obtained from this method with values derived from widely-applied correlations between mass, line broadening and luminosity. Good agreement is found for both radius and black hole mass comparisons. (C) 2013 COSPAR. Published by Elsevier Ltd. All rights reserved.
Autor principal: 
Negrete, CA
Autor/es del IAA: 
Sulentic, Jack W.
DOI: 
10.1016/j.asr.2013.11.037
Revista: 
ADVANCES IN SPACE RESEARCH
Fecha de publicación: 
2014/10/01
Volumen: 
54
Issue: 
7
Páginas: 
1355-1361
Tipo de documento: 
Article
Palabras clave: 
Galaxies: active; Line: formation; Line: profile; Quasars: emission lines; Quasars: general

Exploring low luminosity quasar diversity at z approximate to 2.5 with the Gran Telescopio Canarias

Titulo: 
Exploring low luminosity quasar diversity at z approximate to 2.5 with the Gran Telescopio Canarias
Autores: 
Sulentic, JW; del Olmo, A; Marziani, P
Resumen: 
We present preliminary results from a pencil-beam spectroscopic survey of low-luminosity quasars at z approximate to 2.2 - 2.5. Our goal is to compare these sources with low redshift analogues of similar luminosity. High s/n and moderate resolution spectra were obtained for 15 sources using the faint object spectrograph Osiris on the 10m Gran Telescopio Canarias. The new data make possible an almost unprecedented comparison between sources with the same (moderate) luminosity at widely different cosmic epochs. Preliminary analysis of our spectra confirms the presence of a relatively evolved population of quasars radiating at modest L/L-Edd. A notable difference between the low and high z quasars may involve the presence of lower metallicity quasars at high redshift. (C) 2013 COSPAR. Published by Elsevier Ltd. All rights reserved.
Autor principal: 
Sulentic, JW
Autor/es del IAA: 
Sulentic, Jack W.; del Olmo, Ascension
DOI: 
10.1016/j.asr.2013.09.031
Revista: 
ADVANCES IN SPACE RESEARCH
Fecha de publicación: 
2014/10/01
Volumen: 
54
Issue: 
7
Páginas: 
1401-1405
Tipo de documento: 
Article
Palabras clave: 
Galaxies: abundances; Line: formation; Line: profile; Quasars: emission lines; Quasars: general

Publicaciones IAA-CSIC

Histórico de publicaciones

IAA-CSIC Publications

IAA-CSIC Publications Full Archive