Properties of the H II regions derived using integral field spectroscopy

Here we review some of our more recent results on the observed properties of HII regions using Integral Field Spectroscopy. In particular, we illustrate the use of this technique to study in detail the ionization conditions across the nebulae for galactic HII regions (focused on the Orion Nebula) and the statistical study of large samples of extragalactic HII regions. We review the reported new scaling relation between the local mass density and the oxygen abundance across the disk galaxies and the recently discovered universal gradient for oxygen abundances. We update our previous results the lack of a dependence of the Mass-Metallicity relation with the starformation rate, including new unpublished data. Finally we discuss on the relation between the ionization conditions in the nebulae and the underlying stellar population. All together our results indicate that disk galaxies present a chemical enrichment dominated by an inside-out growth scenario, with a less evident effect of radial migrations and/or outflows. © 2013 Sebastian F. Sánchez.Sebastian F. Sanchez thanks thedirector ofCEFCA, M. Moles, for his sincere support of this project. This study makes use of the data provided by the Calar Alto Legacy Integral Field Area (CALIFA) survey (http://califa.caha.es/). CALIFA is the first legacy survey being performed at Calar Alto. The CALIFA collaboration would like to thank the IAA-CSIC and MPIA-MPG as major partners of the observatory and CAHA itself, for the unique access to telescope time and support in manpower and infrastructures. The CALIFA collaboration also thanks the CAHA staff for the dedication to this project. Based on observations collected at the Centro Astronomico Hispano Aleman (CAHA) at Calar Alto, operated jointly by the Max-Planck-Institut fur Astronomie and the Instituto de Astrof sica de Andalucia (CSIC). The author thanks the anonymous referee for the many useful and detailed comments. The author also thanks P. Papaderos for the useful comments and the suggestions to clean and clarify the text. We thank the Viabilidad, Diseno, Acceso y Mejora funding program, ICTS-2009-10, for supporting the initial development of this project. He thanks the Plan Nacional de Investigacion y Desarrollo funding programs, AYA2010-22111-C03-03 and AYA2010-10904E, of the Spanish Ministerio de Ciencia e Innovacion, for the support given to this project. He thanks the the Ramon y Cajal project RyC-2011-07590 of the spanish Ministerio de Econom a y Competitividad, for the support give to this project. He acknowledges suuport by the Grants nos. M100031241 and M100031201 of the Academy of Sciences of the Czech Republic (ASCR internal support program of international cooperation projects-PIPPMS) and by the Czech Republic program for the long-term development of the research institution no. RVO67985815.Peer Reviewe

More fundamental than the fundamental metallicity relation - The effect of the stellar metallicity on the gas-phase mass-metallicity and gravitational potential-metallicity relations

Context. One of the most fundamental scaling relations in galaxies is observed between metallicity and stellar mass – the massmetallicity relation (MZR) – although recently a stronger dependence of the gas-phase metallicity with the galactic gravitational potential (ΦZR) has been reported. Further dependences of metallicity on other galaxy properties have been revealed, with the star formation rate (SFR) being one of the most studied and debated secondary parameters in the relation (the so-called fundamental metallicity relation). Aims. In this work we explore the dependence of the gas-phase metallicity residuals from the MZR and ΦZR on different galaxy properties in the search for the most fundamental scaling relation in galaxies. Methods. We applied a random forest regressor algorithm on a sample of 3430 nearby star-forming galaxies from the SDSS-IV MaNGA survey. Using this technique, we explored the effect of 147 additional parameters on the global oxygen abundance residuals obtained after subtracting the MZR. Alternatively, we followed a similar approach with the metallicity residuals from the ΦZR. Results. The stellar metallicity of the galaxy is revealed as the secondary parameter in both the MZR and the ΦZR, ahead of the SFR. This parameter reduces the scatter in the relations ~10-15%. We find the 3D relation between gravitational potential, gas metallicity, and stellar metallicity to be the most fundamental metallicity relation observed in galaxies.Juan de la Cierva fellowship (IJC2019-041527-I)Project PID2020-114414GB-100, financed by MCIN/AEI/10.13039/501100011033PAPIITDGAPA AG100622 projectSpanish Ministry of Science and Innovation, project PID2022-136598NB-C31 (ESTALLIDOS

Unveiling a hidden bar-like structure in NGC1087: kinematic and photometric evidence using MUSE/VLT, ALMA and JWST

We report a faint non-axisymmetric structure in NGC\,1087 through the use of JWST Near Infrared Camera { (NIRCam)}, with an associated kinematic counterpart observed as an oval distortion in the stellar velocity map, \ha~and CO~$J=2\rightarrow1$ velocity fields. This structure is not evident in the MUSE optical continuum images but only revealed in the near-IR with the F200W and F300M band filters at $2\mu$m and $3\mu$m respectively. Due to its elongation, this structure resembles a stellar bar although with remarkable differences with respect to conventional stellar bars. Most of the near-IR emission is concentrated within 6\arcsec~\sim500~pc with a maximum extension up to 1.2~kpc. The spatial extension of the large-scale non-circular motions is coincident with the bar, which undoubtedly confirms the presence of a non-axisymmetric perturbation in the potential of NGC\,1087. The oval distortion is enhanced in CO due to its dynamically cold nature rather than in \ha. We found that the kinematics in all phases including stellar, ionized and molecular, can be described simultaneously by a model containing a bisymmetric perturbation; however, we find that an inflow model of gas along the bar major axis is also likely. Furthermore the molecular mass inflow rate associated can explain the observed star formation rate in the bar. This reinforces the idea that bars are mechanisms for transporting gas and triggering star formation. This work contributes to our understanding of non-axisymmetry in galaxies using the most sophisticated data so far.Comment: 14 pages, 8 Figures, accepted for publication in Ap

Serendipitous discovery of a strong-lensed galaxy in integral field spectroscopy from MUSE

2MASX J04035024-0239275 is a bright red elliptical galaxy at redshift 0.0661 that presents two extended sources at 2\arcsec~to the north-east and 1\arcsec~to the south-west. The sizes and surface brightnesses of the two blue sources are consistent with a gravitationally-lensed background galaxy. In this paper we present MUSE observations of this galaxy from the All-weather MUse Supernova Integral-field Nearby Galaxies (AMUSING) survey, and report the discovery of a background lensed galaxy at redshift 0.1915, together with other 15 background galaxies at redshifts ranging from 0.09 to 0.9, that are not multiply imaged. We have extracted aperture spectra of the lens and all the sources and fit the stellar continuum with STARLIGHT to estimate their stellar and emission line properties. A trace of past merger and active nucleus activity is found in the lensing galaxy, while the background lensed galaxy is found to be star-forming. Modeling the lensing potential with a singular isothermal ellipsoid, we find an Einstein radius of 1\farcs45$\pm$0\farcs04, which corresponds to 1.9 kpc at the redshift of the lens and it is much smaller than its effective radius ($r_{\rm eff}\sim$ 9\arcsec). Comparing the Einstein mass and the STARLIGHT stellar mass within the same aperture yields a dark matter fraction of $18 \% \pm 8$ \% within the Einstein radius. The advent of large surveys such as the Large Synoptic Survey Telescope (LSST) will discover a number of strong-lensed systems, and here we demonstrate how wide-field integral field spectroscopy offers an excellent approach to study them and to precisely model lensing effects.Comment: 12 pages, 12 Figures, 4 Tables. Accepted in MNRA

AGN in the CALIFA survey: X-ray detection of nuclear sources

A complete demographic of active galactic nuclei (AGN) is essential to understand the evolution of the Universe. Optical surveys estimate the population of AGN in the local Universe to be of $\sim$ 4%. However, these results could be biased towards bright sources, not affected by the host galaxy attenuation. An alternative method for detecting these objects is through the X-ray emission. In this work, we aim to complement the AGN population of the optical CALIFA survey (941 sources), by using X-ray data from Chandra, which provides the best spatial resolution to date, essential to isolate the nuclear emission from the host galaxy. We study a total of 138 sources with available data. We find 34 new bonafide AGN and 23 AGN candidates, which could increase the AGN population to 7-10\% among the CALIFA survey. X-rays are particularly useful for low-luminosity AGN since they are excluded by the criterion of large equivalent width of the $H\alpha$ emission line when applied to optical selections. Indeed, placing such a restrictive criteria might cause a loss of up to 70% of AGN sources. X-ray detected sources are preferentially located in the right side of the [$OIII$]/$H\beta$ versus [$NII$]/$H\alpha$ diagram, suggesting that this diagram might be the most reliable at classifying AGN sources. Our results support the idea that multi-wavelength studies are the best way to obtain a complete AGN population.Comment: 18 pages, 8 figures, 7 tables, 5 pages of supplementary online material available. Accepted for publication in MNRA

Mildly Suppressed Star Formation in Central Regions of MaNGA Seyfert Galaxies

Negative feedback from accretion onto super-massive black holes (SMBHs), that is to remove gas and suppress star formation in galaxies, has been widely suggested. However, for Seyfert galaxies which harbor less active, moderately accreting SMBHs in the local universe, the feedback capability of their black hole activity is elusive. We present spatially-resolved H$\alpha$ measurements to trace ongoing star formation in Seyfert galaxies and compare their specific star formation rate with a sample of star-forming galaxies whose global galaxy properties are controlled to be the same as the Seyferts. From the comparison we find that the star formation rates within central kpc of Seyfert galaxies are mildly suppressed as compared to the matched normal star forming galaxies. This suggests that the feedback of moderate SMBH accretion could, to some extent, regulate the ongoing star formation in these intermediate to late type galaxies under secular evolution.Comment: 12 pages, 7 figures, accepted by MNRA

Ageing and Quenching through the ageing diagram II: physical characterization of galaxies

The connection between quenching mechanisms, which rapidly turn star-forming systems into quiescent, and the properties of the galaxy population remains difficult to discern. In this work we investigate the physical properties of MaNGA and SAMI galaxies at different stages of their star formation history. Specifically, we compare galaxies with signatures of recent quenching (Quenched) -- $\rm H(\alpha)$ in absorption and low $D_n(4000)$ -- with the rest of the low star-forming and active population (Retired and Ageing, respectively). The analysis is performed in terms of characteristics such as the total stellar mass, half-light radius, velocity-to-dispersion ratio, metallicity, and environment. We find that the Ageing population comprises a heterogeneous mixture of galaxies, preferentially late-type systems, with diverse physical properties. Retired galaxies, formerly Ageing or Quenched systems, are dominated by early-type high-mass galaxies found both at low and dense environments. Most importantly, we find that recently quenched galaxies are consistent with a population of compact low-mass satellite systems, with higher metallicities than their Ageing analogues. We argue that this is compatible with being quenched after undergoing a star-burst phase induced by environmental processes (e.g. ram pressure). However, we also detect a non-negligible fraction of field central galaxies likely quenched by internal processes. This study highlights that, in order to constrain the mechanisms driving galaxy evolution, it is crucial to distinguish between old (Retired) and recently quenched galaxies, thus requiring at least two estimates of the specific star formation rate over different timescales.Comment: Accepted for publication in MNRA