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The Gaia-ESO Survey: the Galactic thick to thin disc transition

Titulo: 
The Gaia-ESO Survey: the Galactic thick to thin disc transition
Autores: 
Reeio-Blanco, A; de Laverny, P; Kordopatis, G; Helmi, A; Hilf, V; Gilmore, G; Wyse, R; Actillekyan, V; Randich, S; Asplund, M; Feltzing, S; Jeffries, R; Micelal, G; Vallenarill, A; Alfaro, E; Prieto, CA; Bensby, T; Bragaglia, A; Flaceomiol, E; Koposov, SE; Korn, A; Lanzafame, A; Paneino, E; Smiliarbel, R; Jaelcson, R; Lewis, J; Magia, L; Morbideli, L; Prisinzano, L; Sacco, G; Worley, CC; Hourthane, A; Bergemann, M; Costado, T; Heiter, U; Joffre, U; Lardo, C; Lind, K; Maiorca, E
Resumen: 
Aims. The nature of the thick disc and its relation to the thin disc is presently an important subject of debate. In fact, the structural and chemo-dynamical transition between disc populations can be used as a test of the proposed models of Galactic disc formation and evolution. Methods. We used the atmospheric parameters, [alpha/Fe] abundances, and radial velocities, which were determined from the Gaia-ESO Survey GIRAFFE spectra of FGK-type stars (first nine months of observations) to provide a chemo-kinematical characterisation of the disc stellar populations. We focussed on a subsample of 1016 stars with high-quality parameters, covering the volume vertical bar Z vertical bar < 4.5 kpc and R in the range 2-13 kpc. Results. We have identified a thin to thick disc separation in the [alpha/Fe] vs. [M/H] plane, thanks to the presence of a low-density region in the number density distribution. The thick disc stars seem to lie in progressively thinner layers above the Galactic plane, as metallicity increases and [alpha/Fe] decreases. In contrast, the thin disc population presents a constant value of the mean distance to the Galactic plane at all metallicities. In addition, our data confirm the already known correlations between V-phi and [M/H] for the two discs. For the thick disc sequence, a study of the possible contamination by thin disc stars suggests a gradient up to 64 +/- 9 km s(-1) dex(-1). The distributions of azimuthal velocity, vertical velocity, and orbital parameters are also analysed for the chemically separated samples. Concerning the gradients with galactocentric radius, we find, for the thin disc, a flat behaviour of the azimuthal velocity, a metallicity gradient equal to -0.058 +/- 0.008 dex kpc(-1) and a very small positive [alpha/Fe] gradient. For the thick disc, flat gradients in [M/H] and [alpha/Fe] are derived. Conclusions. Our chemo-kinematical analysis suggests a picture where the thick disc seems to have experienced a settling process, during which its rotation increased progressively and, possibly, the azimuthal velocity dispersion decreased. At [M/H] approximate to -0.25 dex and [alpha/Fe] approximate to 0.1 dex, the mean characteristics of the thick disc in vertical distance to the Galactic plane, rotation, rotational dispersion, and stellar orbits' eccentricity agree with that of the thin disc stars of the same metallicity, suggesting a possible connection between these two populations at a certain epoch of the disc evolution. Finally, the results presented here, based only on the first months of the Gaia-ESO Survey observations, confirm how crucial large high-resolution spectroscopic surveys outside the solar neighbourhood are today for our understanding of the Milky Way history.
Autor principal: 
Reeio-Blanco, A
Autor/es del IAA: 
Alfaro, E.; Costado, T.
DOI: 
10.1051/0004-6361/201322944
Revista: 
ASTRONOMY & ASTROPHYSICS
Fecha de publicación: 
2014/07
Volumen: 
567
Tipo de documento: 
Article
Palabras clave: 
Galaxy: abundances; Galaxy: disk; Galaxy: stellar content; stars: abundances

Properties of bow-shock sources at the Galactic center

Titulo: 
Properties of bow-shock sources at the Galactic center
Autores: 
Sanchez-Bermudez, J; Schodel, R; Alberdi, A; Muzic, K; Hummel, CA; Pott, JU
Resumen: 
Context. There exists an enigmatic population of massive stars around the Galactic center (GC) that were formed some Myr ago. A fraction of these stars has been found to orbit the supermassive black hole, Sgr A*, in a projected clockwise disk-like structure, which suggests that they were formed in a formerly existing dense disk around Sgr A*. Aims. We focus on a subgroup of objects, the extended, near-infrared (NIR) bright sources IRS 1W, IRS 5, IRS 10W, and IRS 21, that have been suggested to be young, massive stars that form bow shocks through their interaction with the interstellar medium (ISM). Their nature has impeded accurate determinations of their orbital parameters. We aim at establishing their nature and kinematics to test whether they form part of the clockwise disk. Methods. We performed NIR multiwavelength imaging with NACO/VLT using direct adaptive optics (AO) and AO-assisted sparse aperture masking (SAM). We introduce a new method for self-calibration of the SAM point spread function in dense stellar fields. The emission mechanism, morphology, and kinematics of the targets were examined via 3D models, combined with existing models of the gas flow in the central parsec. Results. We confirm previous findings that IRS 21, IRS 1W, and IRS 5 are bow-shocks created by the interaction between mass-losing stars and the interstellar gas. The nature of IRS 10W remains unclear. Our modeling shows that the bow-shock emission is caused by thermal emission, while the scattering of stellar light does not play a significant role. IRS 1W shows a morphology that is consistent with a bow shock produced by an anisotropic stellar wind or by locally inhomogeneous ISM density. Our best-fit models provide estimates of the local proper motion of the ISM in the Northern Arm that agree with previously published models that were based on radio interferometry and NIR spectroscopy. Assuming that all of the sources are gravitationally tied to Sagittarius A*, their orbital planes were obtained via a Monte Carlo simulation. Conclusions. Our sources appear to be Wolf-Rayet stars associated to the last starburst at the GC. Our orbital analysis suggests that they are not part of any of the previously suggested coherent stellar structures, in particular the clockwise disk. We thus add more evidence to recent findings that a large proportion of the massive stars show apparently random orbital orientations, suggesting either that not all of them were formed in the clockwise disk, or that their orbits were randomized rapidly after formation in the disk.
Autor principal: 
Sanchez-Bermudez, J
Autor/es del IAA: 
Sanchez-Bermudez, J.; Schoedel, R.; Alberdi, A.
DOI: 
10.1051/0004-6361/201423657
Revista: 
ASTRONOMY & ASTROPHYSICS
Fecha de publicación: 
2014/07
Volumen: 
567
Tipo de documento: 
Article
Palabras clave: 
techniques: interferometric; circumstellar matter; techniques: high angular resolution; stars: winds, outflows; Galaxy: center
Número de artículo: 
A21

A similar to 12 kpc HI extension and other HI asymmetries in the isolated galaxy CIG 340 (IC 2487)

Titulo: 
A similar to 12 kpc HI extension and other HI asymmetries in the isolated galaxy CIG 340 (IC 2487)
Autores: 
Scott, TC; Sengupta, C; Montenegro, LV; Bosma, A; Athanassoula, E; Sulentic, J; Espada, D; Yun, MS; Argudo-Fernandez, M
Resumen: 
Context. H I kinematic asymmetries are common in late-type galaxies irrespective of environment, although the amplitudes are strikingly low in isolated galaxies. As part of our studies of the HI morphology and kinematics in isolated late-type galaxies we have chosen several very isolated galaxies from the AMIGA sample for HI mapping. We present here the results of HI mapping of CIG 340 (IC 2487) which was selected because its integrated HI spectrum has a very symmetric profile (A(lux) = 1.03 +/- 0.02). Aims. Optical images of the galaxy hinted at a warped disk in contrast to the symmetric integrated HI spectrum profile. Our aim is to determine the extent to which the optical asymmetry is reflected in the resolved HI morphology and kinematics. Methods. Resolved 21-cm HI line mapping has been carried out using the Giant Metrewave Radio Telescope (GMRT). The HI morphology and kinematics from this mapping together with other multi-wavelength data have been used to study the relationship between the HI and stellar components of CIG 340. Results. GMRT observations reveal significant HI morphological asymmetries in CIG 340 despite it's overall symmetric optical form and highly symmetric HI spectrum. The most notable HI features are: 1) a warp in the HI disk (with an optical counterpart), 2) the HI north/south flux ratio = 1.32 is much larger than expected from the integrated HI spectrum profile, and 3) a similar to 45' (12 kpc) HI extension containing similar to 6% of the detected HI mass on the northern side of the disk. Conclusions. Overall, we conclude that in isolated galaxies a highly symmetric HI spectrum can mask significant HI morphological asymmetries which can be revealed by HI interferometric mapping. The northern HI extension appears to be the result of a recent perturbation (10(8) yr), possibly by a satellite which is now disrupted or projected within the disk. But, we cannot rule out that the HI extension and the other observed asymmetries are the result of a long lived dark matter halo asymmetry. This study provides an important step in our ongoing programme to determine the predominant source of HI asymmetries in isolated galaxies. For CIG 340 the isolation from major companions, symmetric HI spectrum, optical morphology and interaction timescales have allowed us to narrow the possible causes the HI asymmetries and identify tests to further constrain the source of the asymmetries.
Autor principal: 
Scott, TC
Autor/es del IAA: 
Scott, T. C.; Verdes Montenegro, L.; Sulentic, J.; Argudo-Fernandez, M.
DOI: 
10.1051/0004-6361/201423701
Revista: 
ASTRONOMY & ASTROPHYSICS
Fecha de publicación: 
2014/07
Volumen: 
567
Tipo de documento: 
Article
Palabras clave: 
galaxies: individual: CIG 340 (IC 2487); galaxies: ISM; radio lines: galaxies

The Gaia-ESO Survey: the first abundance determination of the pre-main-sequence cluster gamma Velorum

Titulo: 
The Gaia-ESO Survey: the first abundance determination of the pre-main-sequence cluster gamma Velorum
Autores: 
Spina, L; Randich, S; Palla, F; Sacco, GG; Magrini, L; Franciosini, E; Morbidelli, L; Prisirizano, L; Alfaro, EJ; Biazzo, K; Frasca, A; Gonzalez-Hernandez, JI; Sousa, SG; Adibekyan, V; Degado-Mena, E; Montes, D; Tabernero, H; Klutsch, A; Gilmore, G; Feitzing, S; Jeffries, RD; Micela, G; Vallenari, A; Bensby, T; Bragaglia, A; Flaccomio, E; Koposov, S; Lanzafame, AC; Pancino, E; Recio-Banco, A; Smiljanie, R; Costado, MT; Darniani, F; Hill, V; Hourihane, A; Jofre, P; de Laverny, P; Masseron, T; Worley, C
Resumen: 
Context. Knowledge of the abundance distribution of star forming regions and young clusters is critical to investigate a variety of issues, from triggered star formation and chemical enrichment by nearby supernova explosions to the ability to form planetary systems. In spite of this, detailed abundance studies are currently available for relatively few regions. Aims. In this context, we present the analysis of the metallicity of the gamma Velorum cluster, based on the products distributed in the first internal release of the Gaia-ESO Survey. Methods. The gamma Velorum candidate members have been observed with FLAMES, using both UVES and Giraffe, depending on the target brightness and spectral type. In order to derive a solid metallicity determination for the cluster, membership of the observed stars must be first assessed. To this aim, we use several membership criteria including radial velocities, surface gravity estimates, and the detection of the photospheric lithium line. Results. Out of the 80 targets observed with UVES, we identify 14 high-probability members. We find that the metallicity of the cluster is slightly subsolar, with a mean [Fe/H] = -0.057 +/- 0.018 dex. Although J08095427-4721419 is one of the high-probability members, its metallicity is significantly larger than the cluster average. We speculate about its origin as the result of recent accretion episodes of rocky bodies of similar to 60 M-circle plus hydrogen-depleted material from the circumstellar disk.
Autor principal: 
Spina, L
Autor/es del IAA: 
Alfaro, E. J.; Costado, M. T.
DOI: 
10.1051/0004-6361/201423527
Revista: 
ASTRONOMY & ASTROPHYSICS
Fecha de publicación: 
2014/07
Volumen: 
567
Tipo de documento: 
Article
Palabras clave: 
stars: abundances; stars: pre-main sequence; open clusters and associations: individual: gamma Velorum; techniques: spectroscopic
Número de artículo: 
A55

Synapses of active galactic nuclei: Comparing X-ray and optical classifications using artificial neural networks

Titulo: 
Synapses of active galactic nuclei: Comparing X-ray and optical classifications using artificial neural networks
Autores: 
Gonzalez-Martin, O; Diaz-Gonzalez, D; Acosta-Pulido, JA; Masegosa, J; Papadakis, IE; Rodriguez-Espinosa, JM; Marquez, I; Hernandez-Garcia, L
Resumen: 
Context. Many classes of active galactic nuclei (AGN) have been defined entirely through optical wavelengths, while the X-ray spectra have been very useful to investigate their inner regions. However, optical and X-ray results show many discrepancies that have not been fully understood yet. Aims. The main purpose of the present paper is to study the synapses (i.e., connections) between X-ray and optical AGN classifications. Methods. For the first time, the newly implemented EFLUXER task allowed us to analyse broad band X-ray spectra of a sample of emission-line nuclei without any prior spectral fitting. Our sample comprises 162 spectra observed with XMM-Newtort/pn of 90 local emission line nuclei in the Palomar sample. It includes, from the optical point of view, starbursts (SB), transition objects (T2). low ionisation nuclear emission line regions (L1.8 and L2), and Seyfert nuclei (S1, S1.8, and S2). We used artificial neural networks (ANNs) to study the connection between X-ray spectra and optical classes. Results. Among the training classes, the ANNs are 90% efficient at classifying the Si, S1.8, and SB classes. The SI and Si 8 classes show a negligible SB-like component contribution with a wide range of contributions from S1- and S1.8-like components, We suggest that this broad range of values is related to the high degree of obscuration in the X-ray regime. When including all the objects in our sample, the Si, S1.8, S2, L1.8, L2/T2/SB-AGIN (SB with indications of AGN activity in the literature), and SI3 classes have similar average X-ray spectra, but these average spectra can be distinguished from class to class. The S2 (L1.8) class is linked to the S1.8 (S1) class with a larger SB-like component than the S1.8 (SB class. The L2, T2, and SB-AGN classes constitute a class in the X-rays similar to the S2 class, albeit with larger portions of SB-like component, We argue that this SB-like component might come from the contribution of the host galaxy emission to the X-rays, which is high when the AGN is weak. Up to 80% of the emission line nuclei and, on average, all the optical classes included in our sample show a significant fraction of S1-like or S1.8-like components. Thus. an AGN-like component seems to be present in the vast majority of the emission line nuclei in our sample. Conclusions. The ANN trained in this paper is not only useful for studying the synergies between the optical and X-ray classifications, but might also be used to infer optical properties from X-ray spectra in surveys like eRosita.
Autor principal: 
Gonzalez-Martin, O
Autor/es del IAA: 
Masegosa, J.; Marquez, I.; Hernandez-Garcia, L.
DOI: 
10.1051/0004-6361/201322592
Revista: 
ASTRONOMY & ASTROPHYSICS
Fecha de publicación: 
2014/07
Volumen: 
567
Tipo de documento: 
Article
Palabras clave: 
galaxies: active; galaxies: Seyfert; X-rays: galaxies
Número de artículo: 
A92

The Mice at play in the CALIFA survey A case study of a gas-rich major merger between first passage and coalescence

Titulo: 
The Mice at play in the CALIFA survey A case study of a gas-rich major merger between first passage and coalescence
Autores: 
Wild, V; Rosales-Ortega, F; Falcon-Barrosso, J; Garcia-Benito, R; Gallazzi, A; Delgado, RMG; Bekeraite, S; Pasquali, A; Johansson, PH; Lorenzo, BG; van de Ven, G; Pawlik, M; Perez, E; Monreal-Ibero, A; Lyubenova, M; Fernandes, RC; Mendez-Abreu, J; Barrera-Ballesteros, J; Kehrig, C; Iglesias-Paramo, J; Bomans, DJ; Marquez, I; Johnson, BD; Kennicut, RC; Husemann, B; Mast, D; Sanchez, SF; Walcher, CJ; Alves, J; Aguerri, AL; Herrero, AA; Bland-Hawthorn, J; Catalian-Torrecilla, C; Florida, E; Gomes, JM; Jahnke, K; Lopez-Sanchez, AR; de Lorenzo-Caceres, A; Marino, RA; Marmol-Queralto, E; Olden, P; del Olmo, A; Papaderos, P; Quirrenbach, A; Vilchez, JM; Ziegler, B
Resumen: 
We present optical integral field spectroscopy (IFS) observations of the Mice, a major merger between two massive (>= 10(11) M-circle dot) gas rich spirals NGC 4676A and B. observed between first passage and final coalescence. The spectra provide stellar and gas kinematics, ionised gas properties, and stellar population diagnostics, over the full optical extent of both galaxies with similar to 1.6 kpc spatial resolution. The Mice galaxies provide a perfect case study that highlights the importance of IFS data for improving our understanding of local galaxies. The impact of first passage on the kinematics of the stars and gas has been significant, with strong bars most likely induced in both galaxies. The barred spiral NOE 4676B exhibits a strong twist in both its stellar and ionised gas disk. The edge on disk galaxy NOE 4676A appears to be bulge free, with a strong bar causing its 'boxy' light profile. On the other hand, the impact of the merger on the stellar populations has been minimal thus fan By combining the IFS data with archival multiwavelength observations we show that star formation induced by the recent close passage has not contributed significantly to the total star formation rate or stellar mass of the galaxies. Both galaxies show bicones of high ionisation gas extending along their minor axes. In NOE 4676A the high gas velocity dispersion and Seyfert-like line ratios at large scaleheight indicate a powerful outflow. Fast shocks (v(s) similar to 350km s(-1)) extend to similar to 6.6 kpc above the disk plane. The measured ram pressure (P/k = 4.8 x 10(6) K cm(-3)) and mass outflow rate (similar to 8-20 M-circle dot yr(-1)) are similar to superwinds from local ultra-luminous infrared galaxies, although NOE 4676A only has a moderate infrared luminosity of 3 x 10(10) L-circle dot. Energy beyond what is provided by the mechanical energy of the starburst appears to be required to drive the outflow, Finally, we compare the observations to mock kinematic and stellar population maps extracted from a hydrodynamical merger simulation. The models show little enhancement in star formation during and following first passage, in agreement with the observations. We highlight areas where IFS data could help further constrain the models.
Autor principal: 
Wild, V
Autor/es del IAA: 
Garcia-Benito, Ruben; Gonzalez Delgado, Rosa M.; Perez, Enrique; Kehrig, Carolina; Iglesias-Paramo, Jorge; Marquez, Isabel; Sanchez, Sebastian F.; del Olmo, Ascension; Vilchez, Jose M.
DOI: 
10.1051/0004-6361/201321624
Revista: 
ASTRONOMY & ASTROPHYSICS
Fecha de publicación: 
2014/07
Volumen: 
567
Tipo de documento: 
Article
Palabras clave: 
galaxies: kinematics and dynamics; galaxies: interactions; galaxies: evolution; galaxies: stellar content; galaxies: Seyfert; techniques: integral field spectroscopy
Número de artículo: 
A132

Photometric Type Ia supernova surveys in narrow-band filters

Titulo: 
Photometric Type Ia supernova surveys in narrow-band filters
Autores: 
Xavier, HS; Abramo, LR; Sako, M; Benitez, N; Calvao, MO; Ederoclite, A; Marin-Franch, A; Molino, A; Reis, RRR; Siffert, BB; Sodre, L
Resumen: 
We study the characteristics of a narrow-band Type Ia supernova (SN) survey through simulations based on the upcoming Javalambre Physics of the accelerating Universe Astrophysical Survey. This unique survey has the capabilities of obtaining distances, redshifts and the SNtype from a single experiment thereby circumventing the challenges faced by the resource-intensive spectroscopic follow-up observations. We analyse the flux measurements signal-to-noise ratio and bias, the SN typing performance, the ability to recover light-curve parameters given by the SALT2 model, the photometric redshift precision from Type Ia SN light curves and the effects of systematic errors on the data. We show that such a survey is not only feasible but may yield large Type Ia SN samples (up to 250 SNe at z < 0.5 per month of search) with low core-collapse contamination (similar to 1.5 per cent), good precision on the SALT2 parameters (average sigma(mB) = 0.063, sigma(x1) = 0.47 and sigma(c) = 0.040) and on the distance modulus (average sigma(mu) = 0.16, assuming an intrinsic scatter sigma(int) = 0.14), with identified systematic uncertainties sigma(sys) less than or similar to 0.10 sigma(stat). Moreover, the filters are narrow enough to detect most spectral features and obtain excellent photometric redshift precision of sigma(z) = 0.005, apart from similar to 2 per cent of outliers. We also present a few strategies for optimizing the survey's outcome. Together with the detailed host galaxy information, narrow-band surveys can be very valuable for the study of SN rates, spectral feature relations, intrinsic colour variations and correlations between SN and host galaxy properties, all of which are important information for SN cosmological applications.
Autor principal: 
Xavier, HS
Autor/es del IAA: 
Benitez, Narciso; Molino, Alberto
DOI: 
10.1093/mnras/stu1611
Revista: 
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Fecha de publicación: 
2014/11/01
Volumen: 
444
Issue: 
3
Páginas: 
2313-2332
Tipo de documento: 
Article
Palabras clave: 
techniques: photometric; surveys; supernovae: general

Traveling planetary wave activity from mesopause region airglow temperatures determined by the Network for the Detection of Mesospheric Change (NDMC)

Titulo: 
Traveling planetary wave activity from mesopause region airglow temperatures determined by the Network for the Detection of Mesospheric Change (NDMC)
Autores: 
Reisin, ER; Scheer, J; Dyrland, ME; Sigernes, F; Deehr, CS; Schmidt, C; Hoppner, K; Bittner, M; Ammosov, PP; Gavrilyeva, GA; Stegman, J; Perminov, VI; Semenov, AI; Knieling, P; Koppmann, R; Shiokawa, K; Lowe, RP; Lopez-Gonzalez, MJ; Rodriguez, E; Zhao, Y; Taylor, MJ; Buriti, RA; Espy, PJ; French, WJR; Eichmann, KU; Burrows, JP; von Savigny, C
Resumen: 
The global distribution of traveling planetary wave (PW) activity in the mesopause region is estimated for the first time from ground-based airglow measurements. Monthly and total mean climatologies of PW power are determined from rotational temperatures measured at 19 sites from 78 degrees N to 76 degrees S which contribute to the Network for the Detection of Mesospheric Change (NDMC). Wave power is expressed as the standard deviation of nocturnal mean temperature around the seasonal temperature variation. The results from 20 degrees N confirm the SABER traveling PW proxy by Offermann et al. (2009, J. Geophys. Res. 114, D06110) at two altitudes. Most sites between 69 degrees S and 69 degrees N show total mean traveling PW activity of about 6 K, and only some high latitude sites have considerably higher activity levels. At the two tropical sites, there is practically no seasonal variation of PW activity. At 70% of the midlatitude sites, the seasonal variation is moderate for most of the year, but it is quite appreciable at all high latitude sites. Results about traveling PW activity at 87 km and 95 km available from several sites signal similar behavior at both altitudes. The total mean climatological results here obtained have further been used to separate the traveling PW contribution from the superposition of wave types contained in OH rotational temperature fluctuations measured by the SCIAMACHY instrument on Envisat. A narrow equatorial wave activity maximum is probably caused by gravity waves, while a tendency towards greater activity at higher northern latitudes may be due to stationary planetary waves. (C) 2014 Elsevier Ltd. All rights reserved.
Autor principal: 
Reisin, ER
Autor/es del IAA: 
Lopez-Gonzalez, M. J.; Rodriguez, E.
DOI: 
10.1016/j.jastp.2014.07.002
Revista: 
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS
Fecha de publicación: 
2014/11
Volumen: 
119
Páginas: 
71-82
Tipo de documento: 
Article
Palabras clave: 
Traveling planetary wave activity; Ground-based airglow observations; Rotational temperature; Network for the Detection of Mesospheric Change (NDMC)

THE DEPENDENCE OF GALACTIC OUTFLOWS ON THE PROPERTIES AND ORIENTATION OF zCOSMOS GALAXIES AT z similar to 1

Titulo: 
THE DEPENDENCE OF GALACTIC OUTFLOWS ON THE PROPERTIES AND ORIENTATION OF zCOSMOS GALAXIES AT z similar to 1
Autores: 
Bordoloi, R; Lilly, SJ; Hardmeier, E; Contini, T; Kneib, JP; Le Fevre, O; Mainieri, V; Renzini, A; Scodeggio, M; Zamorani, G; Bardelli, S; Bolzonella, M; Bongiorno, A; Caputi, K; Carollo, CM; Cucciati, O; de la Torre, S; de Ravel, L; Garilli, B; Iovino, A; Kampczyk, P; Kovac, K; Knobel, C; Lamareille, F; Le Borgne, JF; Le Brun, V; Maier, C; Mignoli, M; Oesch, P; Pello, R; Peng, Y; Montero, EP; Presotto, V; Silverman, J; Tanaka, M; Tasca, L; Tresse, L; Vergani, D; Zucca, E; Cappi, A; Cimatti, A; Coppa, G; Franzetti, P; Koekemoer, A; Moresco, M; Nair, P; Pozzetti, L
Resumen: 
We present an analysis of cool outflowing gas around galaxies, traced by Mg-II absorption lines in the coadded spectra of a sample of 486 zCOSMOS galaxies at 1 <= z <= 1.5. These galaxies span a range of stellar masses (9.45 <= log(10)[M-*/M-circle dot] <= 10.7) and star formation rates (0.14 <= log(10)[SFR/M-circle dot yr(-1)] <= 2.35). We identify the cool outflowing component in the Mg (II) absorption and find that the equivalent width of the outflowing component increases with stellar mass. The outflow equivalent width also increases steadily with the increasing star formation rate of the galaxies. At similar stellar masses, the blue galaxies exhibit a significantly higher outflow equivalent width as compared to red galaxies. The outflow equivalent width shows strong correlation with the star formation surface density (Sigma(SFR)) of the sample. For the disk galaxies, the outflow equivalent width is higher for the face-on systems as compared to the edge-on ones, indicating that for the disk galaxies, the outflowing gas is primarily bipolar in geometry. Galaxies typically exhibit outflow velocities ranging from -150 km s(-1) similar to -200 km s(-1) and, on average, the face-on galaxies exhibit higher outflow velocity as compared to the edge-on ones. Galaxies with irregular morphologies exhibit outflow equivalent width as well as outflow velocities comparable to face on disk galaxies. These galaxies exhibit mass outflow rates >5-7 M-circle dot yr(-1) and a mass loading factor (eta = (M) over dot(out)/SFR) comparable to the star formation rates of the galaxies.
Autor principal: 
Bordoloi, R
Autor/es del IAA: 
Perez Montero, E.
DOI: 
10.1088/0004-637X/794/2/130
Revista: 
ASTROPHYSICAL JOURNAL
Fecha de publicación: 
2014/10/20
Volumen: 
794
Issue: 
2
Tipo de documento: 
Article
Palabras clave: 
galaxies: evolution; galaxies: high-redshift; intergalactic medium; ultraviolet: ISM
Número de artículo: 
130

CLASH-X: A COMPARISON OF LENSING AND X-RAY TECHNIQUES FOR MEASURING THE MASS PROFILES OF GALAXY CLUSTERS

Titulo: 
CLASH-X: A COMPARISON OF LENSING AND X-RAY TECHNIQUES FOR MEASURING THE MASS PROFILES OF GALAXY CLUSTERS
Autores: 
Donahue, M; Voit, GM; Mahdavi, A; Umetsu, K; Ettori, S; Merten, J; Postman, M; Hoffer, A; Baldi, A; Coe, D; Czakon, N; Bartelmann, M; Benitez, N; Bouwens, R; Bradley, L; Broadhurst, T; Ford, H; Gastaldello, F; Grillo, C; Infante, L; Jouvel, S; Koekemoer, A; Kelson, D; Lahav, O; Lemze, D; Medezinski, E; Melchior, P; Meneghetti, M; Molino, A; Moustakas, J; Moustakas, LA; Nonino, M; Rosati, P; Sayers, J; Seitz, S; Van der Wel, A; Zheng, W; Zitrin, A
Resumen: 
We present profiles of temperature, gas mass, and hydrostatic mass estimated from new and archival X-ray observations ofCLASHclusters. We comparemeasurements derived fromXMMand Chandra observations with one another and compare both to gravitational lensing mass profiles derived with CLASH Hubble Space Telescope and Subaru Telescope lensing data. Radial profiles of Chandra andXMMmeasurements of electron density and enclosed gasmass are nearly identical, indicating that differences in hydrostatic masses inferred fromX-ray observations arise from differences in gas-temperature measurements. Encouragingly, gas temperatures measured in clusters by XMM and Chandra are consistent with one another at similar to 100-200 kpc radii, but XMM temperatures systematically decline relative to Chandra temperatures at larger radii. The angular dependence of the discrepancy suggests that additional investigation on systematics such as the XMM point-spread function correction, vignetting, and off-axis responses is yet required. We present the CLASH-X mass-profile comparisons in the form of cosmology-independent and redshift-independent circular-velocity profiles. We argue that comparisons of circular-velocity profiles are the most robust way to assess mass bias. Ratios of Chandra hydrostatic equilibrium (HSE) mass profiles to CLASH lensing profiles show no obvious radial dependence in the 0.3-0.8 Mpc range. However, the mean mass biases inferred from the weak-lensing (WL) and SaWLens data are different. As an example, the weighted-mean value at 0.5 Mpc is < b > = 0.12 for the WL comparison and < b > = -0.11 for the SaWLens comparison. The ratios of XMM HSE mass profiles to CLASH lensing profiles show a pronounced radial dependence in the 0.3-1.0 Mpc range, with a weighted mean mass bias value rising to < b > greater than or similar to 0.3 at similar to 1 Mpc for the WL comparison and < b > approximate to 0.25 for the SaWLens comparison. The enclosed gas mass profiles from both Chandra and XMM rise to a value approximate to 1/8 times the total-mass profiles inferred from lensing at approximate to 0.5 Mpc and remain constant outside of that radius, suggesting that M-gas x 8 profiles may be an excellent proxy for total-mass profiles at greater than or similar to 0.5 Mpc in massive galaxy clusters.
Autor principal: 
Donahue, M
Autor/es del IAA: 
Benitez, Narciso
DOI: 
10.1088/0004-637X/794/2/136
Revista: 
ASTROPHYSICAL JOURNAL
Fecha de publicación: 
2014/10/20
Volumen: 
794
Issue: 
2
Tipo de documento: 
Article
Palabras clave: 
cosmological parameters; dark matter; galaxies: clusters: intracluster medium; gravitational lensing: strong; gravitational lensing: weak; X-rays: galaxies: clusters
Número de artículo: 
136

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