Roberto Terlevich

Instituto Nacional de Astrofísica, Óptica y Electrónica and Institute of Astronomy University of Cambridge.

Context. Blazars are the most numerous class of very-high-energy (VHE; E > 100 GeV) gamma-ray emitters. At present, measured redshifts are available only for about 80% of the VHE gamma-ray sources; this is mainly due to the difficulty in measuring reliable redshifts from their nearly featureless continuum optical spectra. Aims. As the VHE sky is st...

We present a spatially resolved spectroscopic study for the metal poor H ii galaxy J084220+115000 using MEGARA Integral Field Unit observations at the Gran Telescopio Canarias. We estimated the gas metallicity using the direct method for oxygen, nitrogen, and helium and found a mean value of 12 + log (O/H) = 8.03 ± 0.06, and integrated electron den...

We present a spatially resolved spectroscopic study for the metal poor HII galaxy J084220+115000 using MEGARA Integral Field Unit observations at the Gran Telescopio Canarias. We estimated the gas metallicity using the direct method for oxygen, nitrogen and helium and found a mean value of 12+$\log$(O/H)=$8.03\pm$0.06, and integrated electron densi...

We present a spatially resolved spectroscopic study for the metal poor H II galaxy J084220 + 115000 using MEGARA Integral Field Unit observations at the Gran Telescopio Canarias. We estimated the gas metallicity using the direct method for oxygen, nitrogen, and helium and found a mean value of 12 + log (O/H) = 8.03 ± 0.06, and integrated electron d...

The Planck All-Sky Survey to Analyze Gravitationally-lensed Extreme Starbursts (PASSAGES) project aims to identify a population of extremely luminous galaxies using the Planck All-Sky Survey and to explore the nature of their gas fuelling, induced starburst, and the resulting feedback that shape their evolution. Here, we report the identification o...

The Planck All-Sky Survey to Analyze Gravitationally-lensed Extreme Starbursts (PASSAGES) project aims to identify a population of extremely luminous galaxies using the Planck All-Sky Survey and to explore the nature of their gas fuelling, induced starburst, and the resulting feedback that shape their evolution. Here, we report the identification o...

We place novel constraints on the cosmokinetic parameters by using a joint analysis of the newest VLT-KMOS HII galaxies (HIIG) with the Supernovae Type Ia (SNIa) Pantheon sample. We combine the latter data sets in order to reconstruct, in a model independent way, the Hubble diagram to as high redshifts as possible. Using a Gaussian process we deriv...

We present novel cosmological constraints based on a joint analysis of our HII galaxies (HIIG) Hubble relation with the full Planck Cosmic Microwave Background anisotropy spectrum and the Baryon Acoustic Oscillations (BAO) probes. The HII galaxies span a large redshift range (0.088 ≤ z ≤ 2.5), reaching significantly higher redshifts than available...

We place novel constraints on the cosmokinetic parameters by using a joint analysis of the newest VLT-KMOS HII galaxies (HIIG) with the Supernovae Type Ia (SNIa) Pantheon sample. We combine the latter datasets in order to reconstruct, in a model-independent way, the Hubble diagram to as high redshifts as possible. Using a Gaussian process we derive...

We present novel cosmological constraints based on a joint analysis of our HII galaxies (HIIG) Hubble relation with the full Planck Cosmic Microwave Background anisotropy spectrum and the Baryon Acoustic Oscillations (BAO) probes. The HII galaxies span a large redshift range $(0.088 \le z \le 2.5)$, reaching significantly higher redshifts than avai...

We present independent determinations of cosmological parameters using the distance estimator based on the established correlation between the Balmer line luminosity, L(Hβ), and the velocity dispersion (σ) for H ii galaxies (HIIG). These results are based on new VLT-KMOS high spectral resolution observations of 41 high-z (1.3 ≤ z ≤2.6) HIIG combine...

We present independent determinations of cosmological parameters using the distance estimator based on the established correlation between the Balmer line luminosity, L(H$\beta$), and the velocity dispersion ($\sigma$) for HII galaxies (HIIG). These results are based on new VLT-KMOS high spectral resolution observations of 41 high-z ($1.3 \leq$ z $...

The tight correlation between turbulence and luminosity in giant HII regions (GHRs) is not well understood. While the luminosity is due to the UV radiation from the massive stars in the ionizing clusters, it is not clear what powers the turbulence. Observations of the two prototypical GHRs in the local Universe, 30 Doradus and NGC 604, show that pa...

Extragalactic very-high-energy (VHE; E > 100 GeV) sources are unique objects to study the most powerful particle accelerators in nature, as active galactic nuclei are likely sources of ultra-high-energy cosmic rays. BL Lacertae blazars are the most frequent extragalactic objects found in the VHE gamma-ray catalogs. It is very difficult to estimate...

We here report the detection of extended He ii λ4686 nebular emission in the central region of NGC 1569 using the integral field spectrograph MEGARA at the 10.4 m Gran Telescopio Canarias. The observations cover a field of view (FoV) of 12.5 arcsec × 11.3 arcsec at a seeing-limited spatial resolution of ∼15 pc and at a spectral resolution of R = 60...

We here report the detection of extended HeII4686 nebular emission in the central region of NGC1569 using the integral field spectrograph MEGARA at the 10.4-m Gran Telescopio Canarias. The observations cover a Field of View (FoV) of 12.5 arcsec x 11.3 arcsec at seeing-limited spatial resolution of ~15 pc and at a spectral resolution of R=6000 in th...

We study the kinematics of the giant H ii regions NGC 5455 and NGC 5471 located in the galaxy M101, using integral field observations that include the H β and [O iii]$\, \lambda$ 5007 emission lines, obtained with the Keck Cosmic Web Imager. We analyse the line profiles using both single and multiple Gaussian curves, gathering evidence for the pres...

We study the kinematics of the giant H II regions NGC 5455 and NGC 5471 located in the galaxy M101, using integral field observations that include the Hbeta and [O III] 5007 emission lines, obtained with the Keck Cosmic Web Imager. We analyse the line profiles using both single and multiple Gaussian curves, gathering evidence for the presence of se...

New FLAMES/GIRAFFE public data allows to revisit the issue of the origin of the supersonic turbulence inferred in the ionized gas of Giant HII Regions using the prototypical 30~Doradus nebula in the LMC as a guide. We find that the velocity width of the integrated H$\alpha$ line-profile of 30~Doradus can only be explained by the motion of macroscop...

We present new high spectral resolution observations of 15 high-z (1.3 ≤ z ≤2.5) H II galaxies (H II G) obtained with MOSFIRE at the Keck Observatory. These data, combined with already published data for another 31 high-z and 107 z ≤0.15 H II G, are used to obtain new independent cosmological results using the distance estimator based on the establ...

We present new high spectral resolution observations of 15 high-z ($1.3 \leq$ z $\leq 2.5$) HII Galaxies (HIIG) obtained with MOSFIRE at the Keck Observatory. These data, combined with already published data for another 31 high-z and 107 z $\leq 0.15$ HIIG, are used to obtain new independent cosmological results using the distance estimator based o...

This work presents a Bayesian algorithm to fit the recombination and collisionally excited line spectra of gas photoionized by clusters of young stars. The current model consists in fourteen dimensions: two electron temperatures, one electron density, the extinction coefficient, the optical depth on the $HeI$ recombination lines and nine ionic spec...

This work presents a Bayesian algorithm to fit the recombination and collisionally excited line spectra of gas photoionized by clusters of young stars. The current model consists in fourteen dimensions: two electron temperatures, one electron density, the extinction coefficient, the optical depth on the HeI recombination lines and nine ionic specie...

This work presents a Bayesian algorithm to fit the recombination and collisionally excited line spectra of gas photoionized by clusters of young stars. The current model consists in fourteen dimensions: two electron temperatures, one electron density, the extinction coefficient, the optical depth on the HeI recombination lines and nine ionic specie...

We present new spectroscopic data of the BL Lac RGB 2243 + 203, and its surroundings, obtained with the OSIRIS Multi Object Spectrograph (MOS) mounted in the Gran Telescopio Canarias (GTC). The spectra of neither the BL Lac nor its host galaxy show any spectral feature, thus hindering direct determination of its redshift. The spectroscopic redshift...

We present new spectroscopic data of the BL Lac RGB 2243+203, and its surroundings, obtained with the OSIRIS Multi Object Spectrograph (MOS) mounted in the Gran Telescopio Canarias (GTC). The spectra of neither the BL Lac nor its host galaxy show any spectral feature, thus hindering direct determination of its redshift. The spectroscopic redshift d...

Massive starforming regions like Giant H II Regions (GHIIR) and H II Galaxies (HIIG) are emission line systems ionized by compact young massive star clusters (YMC) with masses ranging from 104M⊙ to 108M⊙. We model the photometric and dynamical evolution over a Hubble time of the massive gravitationally bound systems that populate the tight relation...

The primordial helium abundance YP is calculated using sulphur as metallicity tracer in the classical methodology (with YP as an extrapolation of Y to zero metals). The calculated value, YP, S= 0.244 ± 0.006, is in good agreement with the estimate from the Planck experiment, as well as, determinations in the literature using oxygen as the metallici...

Massive starforming regions like Giant HII Regions (GHIIR) and HII Galaxies (HIIG) are emission line systems ionized by compact young massive star clusters (YMC) with masses ranging from $10^4$M$_\odot$ to $10^8$M$_\odot$. We model the photometric and dynamical evolution over a Hubble time of the massive gravitationally bound systems that populate...

MEGARA is the new generation IFU and MOS optical spectrograph built for the 10.4m Gran Telescopio CANARIAS (GTC). The project was developed by a consortium led by UCM (Spain) that also includes INAOE (Mexico), IAA-CSIC (Spain) and UPM (Spain). The instrument arrived to GTC on March 28 th 2017 and was successfully integrated and commissioned at the...

The primordial helium abundance $Y_P$ is calculated using sulphur as metallicity tracer in the classical methodology (with $Y_P$ as an extrapolation of $Y$ to zero metals). The calculated value, $Y_{P,\,S}=0.244\pm0.006$, is in good agreement with the estimate from the Planck experiment, as well as, determinations in the literature using oxygen as...

The relationship between the integrated H$\beta$ line luminosity and the velocity dispersion of the ionized gas of HII galaxies and giant HII regions represents an exciting standard candle that presently can be used up to redshifts z ~ 4. Locally it is used to obtain precise measurements of the Hubble constant by combining the slope of the relation...

We present the results of our search near the end of the Reionization Epoch for faint galaxies. This has been done using very deep OSIRIS images obtained at the Gran Telescopio Canarias (GTC). Our observations focus around two close,massive Lyman a emitters (LAEs) at redshift 6.5, discovered in the SXDS field within a large-scale overdense region....

We have obtained intermediate resolution spectra for about 30 galaxies, normal and active, in the near infrared region covering the CaII triplet (λλ 7800–9300 Å). The data were obtained with the INT at the Roque de los Muchachos Observatory in La Palma, Spain using the Intermediate Dispersion Spectrograph and a GEC CCD detector. Details of these ob...

A very small minority of all galaxies exhibit activity in their nuclear regions. The best known and most studied signature of nuclear activity is the presence of emission lines in the optical spectrum. In fact, active galaxies are classified as Seyferts, Liners or Starburst galaxies according to the strengths, widths and intensity ratios of their n...

A significant fraction of all spiral galaxies exhibit some type of “activity” in their nuclear regions as evidenced by the presence of emission lines in their optical spectrum (Keel, 1982; Cetty-Veron and Veron, 1985). It has become standard to classify emission-line galaxies into two main groups: “active” having Seyfert or Liner nuclei and “inacti...

Motions of nearby elliptical galaxies reveal a large-scale velocity flow relative to cosmic rest towards the point 1=307±10, b = 9±10. The data are fit best by a two-component flow model. The smaller component is due to Virgo, which induces a velocity at the Local Group of 250 km/s. The main flow is due to a more massive concentration located a dis...

The peculiar motions for spiral galaxies and elliptical galaxies within V = 3500 km/s are compared to the model predictions of the mass concentration (MC) velocity field model of Lynden-Bell et al. The large-scale motions defined by over 600 galaxies from three independent sets of data (Aaronson et al.; de Vaucouleurs and Peters and elliptical gala...

The main goal of this study is to characterise the stellar populations in very low metallicity galaxies. We have obtained broad U, B, R, I, J, H, K, intermediate Str\"omgren y and narrow H{\alpha} and [OIII] deep images of the Wolf-Rayet, Blue Compact Dwarf, H II galaxy Tol 02. We have analysed the low surface brightness component, the stellar clus...

We present the results of our search for the faint galaxies near the end of the Reionisation Epoch. This has been done using very deep OSIRIS images obtained at the Gran Telescopio Canarias (GTC). Our observations focus around two close, massive Lyman Alpha Emitters (LAEs) at redshift 6.5, discovered in the SXDS field within a large-scale overdense...

The correlation between emission-line luminosity (L) and profile width (sigma) for HII Galaxies provides a powerful method to measure the distances to galaxies over a wide range of redshifts. In this paper we use SDSS spectrophotometry to explore the systematics of the correlation using the [OIII]5007 lines instead of Halpha or Hbeta to measure lum...

The correlation between emission-line luminosity (L) and profile width (sigma) for HII Galaxies provides a powerful method to measure the distances to galaxies over a wide range of redshifts. In this paper we use SDSS spectrophotometry to explore the systematics of the correlation using the [OIII]5007 lines instead of Halpha or Hbeta to measure lum...

We report on the redshift of the BL Lac object 3FGL J0909.0+2310 based on observations obtained with the OSIRIS Multi Object Spectrograph (MOS) mounted on the 10.4-m Gran Telescopio Canarias. A redshift of 0.432+/-0.002 was obtained by the identification of three absorption features (CaII K&H and G-band) detected in the spectrum of the BL Lac host...

We use the HII galaxies $L - \sigma$ relation and the resulting Hubble expansion cosmological probe of a sample of just 25 high-$z$ (up to $z \sim 2.33$) HII galaxies, in a joint likelihood analysis with other well tested cosmological probes (CMB, BAOs) in an attempt to constrain the dark energy equation of state (EoS). The constraints, although st...

ID11 is an actively star-forming, extremely compact galaxy and Lyα emitter at $\textit{z}$ = 3.117 that is gravitationally magnified by a factor of ~17 by the cluster of galaxies $\textit{Hubble}$ Frontier Fields AS1063. The observed properties of this galaxy resemble those of low luminosity HII galaxies or giant HII regions such as 30 Doradus in t...

MEGARA (Multi-Espectrografo en GTC de Alta Resolucion para Astronomia) is an optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) designed for the GTC 10.4m telescope in La Palma that is being built by a Consortium led by UCM (Spain) that also includes INAOE (Mexico), IAA-CSIC (Spain), and UPM (Spain). The instrument is currently f...

ID11 is an actively star-forming, extremely compact galaxy and Lyα emitter at z = 3.117 that is gravitationally magnified by a factor of ~17 by the cluster of galaxies Hubble Frontier Fields AS1063. The observed properties of this galaxy resemble those of low luminosity HII galaxies or giant HII regions such as 30 Doradus in the Large Magellanic Cl...

We present 8.5″ resolution 1.1mm continuum imaging and CO spectroscopic redshift measurements of eight extremely bright submillimetre galaxies identified from the Planck and Herschel surveys, taken with the Large Millimeter Telescope's AzTEC and Redshift Search Receiver instruments. We compiled a candidate list of high redshift galaxies by cross-co...

We have assembled a new sample of some of the most FIR-luminous galaxies in the Universe and have imaged them in 1.1 mm dust emission and measured their redshifts 1 < z < 4 via CO emission lines using the 32-m Large Millimeter Telescope / Gran Telescopio Milimétrico (LMT/GTM). Our sample of 31 submm galaxies (SMGs), culled from the Planck and Hersc...

Measuring redshifted CO line emission is an unambiguous method for obtaining an accurate redshift and total cold gas content of optically faint, dusty starburst systems. Here, we report the first successful spectroscopic redshift determination of AzTEC J095942.9+022938 (‘COSMOS AzTEC-1’), the brightest 1.1 mm continuum source found in the AzTEC/Jam...

We present photometry in U, B, V, R and I continuum bands and in Hα and Hβ emission lines for a sample of 336 circumnuclear star-forming regions located in early-type spiral galaxies with different levels of activity in their nuclei. They are nearby galaxies, with distances less than 100 Mpc, 60 per cent of which are considered as interacting objec...

I have selected a sample of 504 HII like-starburst galaxies according to the equivalent widths in their emission lines in a range of redshift of 0.1 < z < 3.4 from the literature, in order to assess the validity of the L(Hβ) - σ relation at high redshift and its use as an accurate distance estimator. The physical parameters for the sample at high r...

We report the first results of a programme aimed at studying the properties of high-redshift galaxies with ongoing massive and dominant episodes of star formation (H ii galaxies). We use the L(Hβ)–σ distance estimator based on the correlation between the ionized gas velocity dispersions and Balmer emission line luminosities of H ii galaxies and Gia...

This work investigates the main mechanism(s) that regulate the specific star formation rate (SSFR) in nearby galaxies, cross-correlating two proxies of this quantity -- the equivalent width of the \Ha\ line and the $(u-r)$ colour -- with other physical properties (mass, metallicity, environment, morphology, and the presence of close companions) in...

From the structure of PHL 293B and the physical properties of its ionizing cluster and based on results of hydrodynamic models, we point at the various events required to explain in detail the emission and absorption components seen in its optical spectrum. We ascribe the narrow and well centered emission lines, showing the low metallicity of the g...

MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is the future intermediate-resolution optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) of the 10.4m GTC telescope. The instrument can be used to observe either a contiguous (100% filling factor) field-of-view of 12.5×11.3 arcsec^{2} or 92 objects anywhere in...

X-shooter and WHT-ISIS spectra of the star-forming galaxy PHL 293B also known as A2228-00 and SDSS J223036.79-000636.9 are presented in this paper. We find broad (FWHM = 1000 km s−1) and very broad (FWZI = 4000 km s−1) components in the Balmer lines, narrow absorption components in the Balmer series blueshifted by 800 km s−1, previously undetected...

The validity of the emission-line luminosity versus ionized gas velocity dispersion (L–σ) correlation for H ii galaxies (HIIGx) and its potential as an accurate distance estimator are assessed. For a sample of 128 local (0.02 ≲ z ≲ 0.2) compact HIIGx with high equivalent widths of their Balmer emission lines, we obtained the ionized gas velocity di...

MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is an optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) designed for the GTC 10.4m telescope in La Palma. MEGARA offers two IFU fiber bundles, one covering 12.5x11.3 arcsec2 with a spaxel size of 0.62 arcsec (Large Compact Bundle; LCB) and another one coverin...

The molecular phase of the interstellar medium (ISM) in galaxies offers fundamental insight for understanding star-formation processes and how stellar feedback affects the nuclear activity of certain galaxies. We present here Large Millimeter Telescope spectra obtained with the Redshift Search Receiver, a spectrograph that cover simultaneously the...

We report the first results of a long term program aiming to provide accurate independent estimates of the Hubble constant (H_0 ) and the Dark Energy equation of state parameter (w) using the L(Hβ )-σ distance estimator for Giant HII regions and HII galaxies (HIIGs). We have used VLT and Subaru high dispersion spectroscopic observations of a local...

We present a study of the close (∼ < 200h −1 75 kpc) environment of 110 relatively local (z ∼ < 0.16) HII galaxies, selected from the Sloan Digital Sky Survey (SDSS; DR7). We use available spectroscopic and photometric redshifts in order to investigate the presence of a close and possibly interacting companion galaxy. Our aim is to compare the phys...

We present a study of the close (≲ 200 h75-1 kpc) environment of 110 relatively local (z ≲ 0.16) HII galaxies, selected from the Sloan Digital Sky Survey (SDSS; DR7). We use available spectroscopic and photometric redshifts to investigate the presence of a close and possibly interacting companion galaxy. Our aim is to compare the physical propertie...

[Abbreviated] We review the results of high dispersion spectroscopy of 17 circumnuclear starforming regions (CNSFRs) in 3 nearby early spiral galaxies, NGC2903, NGC3310 and NGC3351. We find that single Gaussian fitting to the H?beta and [OIII]5007A line profiles results in velocity dispersions around 32km/s and 52km/s, respectively, while the IR Ca...

The determination of oxygen abundance in nebulae requires measuring a significant number of emission lines distributed along a wide spectral range. The required measurements are hard to obtain at high redshift, where sources are very faint, and where the accessible spectral range is limited. These difficulties are often overcome using empirical rel...

We have computed with a fine time grid the evolution of the elemental abundances of He, C, N and O ejected by young (t < 20Myr) and massive (M = 10^{6} M_{⊙} coeval stellar cluster with a Salpeter initial mass function (IMF) over a wide range of initial abundances. Our computations incorporate the mass loss from massive stars (M ≥0 M_{⊙}) during th...

H II galaxies integrated properties have been widely studied. However, little is known about the individual H II regions and their photoionizing stellar clusters. To broaden our knowledge on star formation in low mass star-forming galaxies (like H II galaxies) it is necessary to answer questions like: How does the star formation distributes along t...

In these proceedings we summarize the characteristics and current status of MEGARA, the future optical IFU and MOS for the 10.4 m GTC. MEGARA is being built by a Consortium led by the UCM (Spain) that also includes the INAOE (Mexico), the IAA-CSIC (Spain) and the UPM (Spain). The MEGARA IFU offers two different bundles, one called LCB with a field-...

Integral field spectroscopy (IFS) is presented for star forming regions in M33. A central area of 300 x 500 pc^2 and the external HII region IC 132, at a galactocentric distance {\sim} 19arcmin (4.69 kpc) were observed with the Potsdam Multi Aperture Spectrophotometer (PMAS) instrument at the 3.5 m telescope of the Calar Alto Hispano- Alem\'an obse...

In these proceedings we give a summary of the characteristics and current status of the MEGARA instrument, the future optical IFU and MOS for the 10.4-m Gran Telescopio Canarias (GTC). MEGARA is being built by a Consortium of public research institutions led by the Universidad Complutense de Madrid (UCM, Spain) that also includes INAOE (Mexico), IA...

We describe a simple step-by-step guide to qualitative interpretation of galaxy spectra. Rather than an alternative to existing automated tools, it is put forward as an instrument for quick-look analysis, and for gaining physical insight when interpreting the outputs provided by automated tools. Though the recipe is of general application, it was d...

We present the measurements of gas and stellar velocity dispersions in 17 circumnuclear star-forming regions (CNSFRs) and the nuclei of three barred spiral galaxies: NGC2903, NGC3310 and NGC3351 from high dispersion spectra. The stellar dispersions have been obtained from the CaII triplet (CaT) lines at 8494, 8542, 8662A, while the gas velocity dis...

We have computed with a fine time grid the evolution of the elemental abundances of He, C, N and O ejected by young (t < 20 Myr) and massive (M = 106 M⊙) coeval stellar cluster with a Salpeter initial mass function (IMF) over a wide range of initial abundances. Our computations incorporate the mass loss from massive stars (M ≥ 30 M⊙) during their w...

We report the first results of a long-term programme aiming to provide accurate independent estimates of the Hubble constant (H0) using the L(Hβ)–σ distance estimator for giant extragalactic H ii regions (GEHR) and H ii galaxies. We have used Very Large Telescope and Subaru high-dispersion spectroscopic observations of a local sample of H ii galaxi...

We investigate the utility of the Tunable Filters (TFs) for obtaining flux calibrated emission line maps of extended objects such as galactic nebulae and nearby galaxies, using the OSIRIS instrument at the 10.4-m GTC. Despite a relatively large field of view of OSIRIS (8'x8'), the change in the wavelength across the field (~80 Ang) and the long-tai...

We use the self-consistent model technique developed by Mart\'in-Manj\'on et al. (2008) that combines the chemical evolution with stellar population synthesis and photo-ionization codes, to study the star formation scenarios capable of reproducing the observed properties of star-forming galaxies. The comparison of our model results with a database...

We study the evolution of the elemental abundances of He, C, N y O of a stellar cluster during the first 20 Myr by taking into account the contribution of the WRs stars. In order to do that, we calculate the ejected mass and the proportion of the different chemical elements in the stellar cluster with solar initial abundance Z = Z_⊙ and an initial...

Using Halpha and [OIII]lambda5007 images taken with the 4.1 m SOAR telescope we have created a catalogue of HII regions in the HII galaxies Tol 1358-328 and Mrk 1318. This catalogue is the first step of a work that intends to characterize star formation and its impact in the surrounding interstellar medium (ISM) in extremely young HII galaxies.

OSIRIS (Optical System for Imaging and low Resolution Integrated Spectroscopy) is the first light instrument of the Gran Telescopio Canarias (GTC). It provides a flexible and competitive tunable filter (TF). Since it is based on a Fabry-Perot interferometer working in a collimated beam, the TF transmission wavelength depends on the position of the...

We explore the possibility of setting stringent constraints to the dark energy equation of state using alternative cosmic tracers like (a) the Hubble relation using H ii galaxies, which can be observed at much higher redshifts (z≲ 3.5) than those currently traced by Type Ia supernovae (SNeIa) samples, and (b) the large-scale structure using the clu...

We explore the possibility of setting stringent constraints to the Dark Energy equation of state using alternative cosmic tracers like: (a) the Hubble relation using HII galaxies, which can be observed at much higher redshifts (z~3.5) than those currently traced by SNIa samples, and (b) the large-scale structure using the clustering of X-ray select...

We analyse high signal-to-noise ratio spectrophotometric observations acquired simultaneously with TWIN, a double-arm spectrograph, from 3400 to 10 400 Å of three star-forming regions in the H ii galaxy SDSS J165712.75+321141.4. We have measured four line temperatures –Te([O iii]), Te([S iii]), Te([O ii]) and Te([S ii]) – with high-precision, rms e...