Examinando por Autor "Dall'Ora, M."
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Ítem Chemical Compositions of Field and Globular Cluster RR Lyrae Stars. I. NGC 3201(Institute of Physics Publishing, 2018-09) Magurno, D.; Sneden, C.; Braga, V.F.; Bono, G.; Mateo, M.; Persson, S.E.; Dall'Ora, M.; Marengo, M.; Monelli, M.; Neeley, J.R.We present a detailed spectroscopic analysis of horizontal branch stars in the globular cluster NGC 3201. We collected optical (4580-5330), high-resolution (∼34,000), high signal-to-noise ratio (∼200) spectra for 11 RR Lyrae stars and one red horizontal branch star with the multifiber spectrograph M2FS with the 6.5 m Magellan telescope at the Las Campanas Observatory. From measured equivalent widths, we derived atmospheric parameters and abundance ratios for (Mg, Ca, and Ti), iron-peak (Sc, Cr, Ni, and Zn), and s-process (Y) elements. We found that NGC 3201 is a homogeneous, monometallic ([Fe/H] = -1.47 ± 0.04), enhanced ([/Fe] = 0.37 ± 0.04) cluster. The relative abundances of the iron-peak and s-process elements were found to be consistent with solar values. In comparison with other large stellar samples, NGC 3201 RR Lyraes have similar chemical enrichment histories as do those of other old (t ≥ 10 Gyr) Halo components (globular clusters; red giants; blue and red horizontal branch stars; and RR Lyraes). We also provided a new average radial velocity estimate for NGC 3201 by using a template velocity curve to overcome the limit of single-epoch measurements of variable stars: Vrad = 494 ± 2 km s-1 (σ = 8 km s-1). © 2018. The American Astronomical Society. All rights reserved.Ítem LSQ14efd: Observations of the cooling of a shock break-out event in a type Ic Supernova(Oxford University Press, 2017-11) Barbarino, C.; Botticella, M.T.; Dall'Ora, M.; Valle, M. Della; Benetti, S.; Lyman, J.D.; Smartt, S.J.; Arcavi, I.; Baltay, C.; Bersier, D.; Dennefeld, M.; Ellman, N.; Fraser, M.; Gal-Yam, A.; Hosseinzadeh, G.; Howell, D.A.; Inserra, C.; Kankare, E.; Leloudas, G.; Maguire, K.; McCully, C.; Mitra, A.; McKinnon, R.; Olivares, E.F.; Pignata, G.; Rabinowitz, D.; Rostami, S.; Smith, K.W.; Sullivan, M.; Valenti, S.; Yaron, O.; young, D.We present the photometric and spectroscopic evolution of the type Ic supernova LSQ14efd, discovered by the La SillaQUEST survey and followed by PESSTO. LSQ14efdwas discovered fewdays after explosion and the observations cover up to~100 d. The early photometric points show the signature of the cooling of the shock break-out event experienced by the progenitor at the time of the supernova explosion, one of the first for a type Ic supernova. A comparison with type Ic supernova spectra shows that LSQ14efd is quite similar to the type Ic SN 2004aw. These two supernovae have kinetic energies that are intermediate between standard Ic explosions and those which are the most energetic explosions known (e.g. SN 1998bw).We computed an analytical model for the light-curve peak and estimated the mass of the ejecta 6.3 ± 0.5M⊙, a synthesized nickel mass of 0.25M⊙ and a kinetic energy of Ekin = 5.6 ± 0.5 × 1051 erg. No connection between LSQ14efd and a gamma-ray burst event could be established. However we point out that the supernova shows some spectroscopic similarities with the peculiar SN-Ia 1999ac and the SN-Iax SN 2008A. A core-collapse origin is most probable considering the spectroscopic, photometric evolution and the detection of the cooling of the shock breakout. © 2017 The Authors.Ítem Observations of field and cluster RR Lyræ with Spitzer. Towards high precision distances with Population II stellar tracers(EDP Sciences, 2017-09) Marengo, M.; Neeley, J.; Bono, G.; Braga, V.; Dall'Ora, M.; Marconi, M.; Trueba, N.; Magurno, D.We present our project to calibrate the RR Lyræ period-luminosity-metallicity relation using a sample of Galactic calibrators in the halo and globular clusters.Ítem On the Chemical Abundances of Miras in Clusters: V1 in the Metal-rich Globular NGC 5927(Institute of Physics Publishing, 2018-03) D'Orazi, V.; Magurno, D.; Bono, G.; Matsunaga, N.; Braga, V.F.; Elgueta, S.S.; Fukue, K.; Hamano, S.; Inno, L.; Kobayashi, N.; Kondo, S.; Monelli, M.; Nonino, M.; Przybilla, N.; Sameshima, H.; Saviane, I.; Taniguchi, D.; Thevenin, F.; Urbaneja-Perez, M.; Watase, A.; Arai, A.; Bergemann, M.; Buonanno, R.; Dall'Ora, M.; Da Silva, R.; Fabrizio, M.; Ferraro, I.; Fiorentino, G.; Francois, P.; Gilmozzi, R.; Iannicola, G.; Ikeda, Y.; Jian, M.; Kawakita, H.; Kudritzki, R.P.; Lemasle, B.; Marengo, M.; Marinoni, S.; Martínez-Vázquez, C.E.; Minniti, D.; Neeley, J.; Otsubo, S.; Prieto, J.L.; Proxauf, B.; Romaniello, M.; Sanna, N.; Sneden, C.; Takenaka, K.; Tsujimoto, T.; Valenti, E.; Yasui, C.; Yoshikawa, T.; Zoccali, M.We present the first spectroscopic abundance determination of iron, α-elements (Si, Ca, and Ti), and sodium for the Mira variable V1 in the metal-rich globular cluster NGC 5927. We use high-resolution (R ∼ 28,000), high signal-to-noise ratio (∼200) spectra collected with WINERED, a near-infrared (NIR) spectrograph covering simultaneously the wavelength range 0.91-1.35 μm. The effective temperature and the surface gravity at the pulsation phase of the spectroscopic observation were estimated using both optical (V) and NIR time-series photometric data. We found that the Mira is metal-rich ([Fe/H] = -0.55 ± 0.15) and moderately α-enhanced ([α/Fe] = 0.15 ± 0.01, σ = 0.2). These values agree quite well with the mean cluster abundances based on high-resolution optical spectra of several cluster red giants available in the literature ([Fe/H] = - 0.47 ± 0.06, [α/Fe] = + 0.24 ± 0.05). We also found a Na abundance of +0.35 ±0.20 that is higher than the mean cluster abundance based on optical spectra (+0.18 ± 0.13). However, the lack of similar spectra for cluster red giants and that of corrections for departures from local thermodynamical equilibrium prevents us from establishing whether the difference is intrinsic or connected with multiple populations. These findings indicate a strong similarity between optical and NIR metallicity scales in spite of the difference in the experimental equipment, data analysis, and in the adopted spectroscopic diagnostics. © 2018. The American Astronomical Society. All rights reserved.Ítem On the RR Lyrae Stars in Globulars. V. the Complete Near-infrared (JHK s) Census of ω Centauri RR Lyrae Variables(nstitute of Physics Publishing, 2018-03) Braga, V.F.; Stetson, P.B.; Bono, G.; Dall'Ora, M.; Ferraro, I.; Fiorentino, G.; Iannicola, G.; Marconi, M.; Marengo, M.; Monson, A.J.; Neeley, J.; Persson, S.E.; Beaton, R.L.; Buonanno, R.; Calamida, A.; Castellani, M.; Carlo, E.D.; Fabrizio, M.; Freedman, W.L.; Inno, L.; Madore, B.F.; Magurno, D.; Marchetti, E.; Marinoni, S.; Marrese, P.; Matsunaga, N.; Minniti, D.; Monelli, M.; Nonino, M.; Piersimoni, A.M.; Pietrinferni, A.; Prada-Moroni, P.; Pulone, L.; Stellingwerf, R.; Tognelli, E.; Walker, A.R.; Valenti, E.; Zoccali, M.We present a new complete near-infrared (NIR, JHK s) census of RR Lyrae stars (RRLs) in the globular ω Cen (NGC 5139). We collected 15,472 JHK s images with 4-8 m class telescopes over 15 years (2000-2015) covering a sky area around the cluster center of 60 ×34 arcmin2. These images provided calibrated photometry for 182 out of the 198 cluster RRL candidates with 10 to 60 measurements per band. We also provide new homogeneous estimates of the photometric amplitude for 180 (J), 176 (H) and 174 (K s) RRLs. These data were supplemented with single-epoch JK s magnitudes from VHS and with single-epoch H magnitudes from 2MASS. Using proprietary optical and NIR data together with new optical light curves (ASAS-SN) we also updated pulsation periods for 59 candidate RRLs. As a whole, we provide JHK s magnitudes for 90 RRab (fundamentals), 103 RRc (first overtones) and one RRd (mixed-mode pulsator). We found that NIR/optical photometric amplitude ratios increase when moving from first overtone to fundamental and to long-period (P > 0.7 days) fundamental RRLs. Using predicted period-luminosity-metallicity relations, we derive a true distance modulus of 13.674 ± 0.008 ±0.038 mag (statistical error and standard deviation of the median) based on spectroscopic iron abundances, and of 13.698 ±0.004 ±0.048 mag based on photometric iron abundances. We also found evidence of possible systematics at the 5%-10% level in the zero-point of the period-luminosity relations based on the five calibrating RRLs whose parallaxes had been determined with the HST. © 2018. The American Astronomical Society. All rights reserved.Ítem PESSTO: Survey description and products from the first data release by the Public ESO Spectroscopic Survey of Transient Objects(EDP Sciences, 2015-07) Smartt, S.J.; Valenti, S.; Fraser, M.; Inserra, C.; Young, D.R.; Sullivan, M.; Pastorello, A.; Benetti, S.; Gal-Yam, A.; Knapic, C.; Molinaro, M.; Smareglia, R.; Smith, K.W.; Taubenberger, S.; Yaron, O.; Anderson, J.P.; Ashall, C.; Balland, C.; Baltay, C.; Barbarino, C.; Bauer, F.E.; Baumont, S.; Bersier, D.; Blagorodnova, N.; Bongard, S.; Botticella, M.T.; Bufano, F.; Bulla, M.; Cappellaro, E.; Campbell, H.; Cellier-Holzem, F.; Chen, T.-W.; Childress, M.J.; Clocchiatti, A.; Contreras, C.; Dall'Ora, M.; Danziger, J.; De Jaeger, T.; De Cia, A.; Della Valle, M.; Dennefeld, M.; Elias-Rosa, N.; Elman, N.; Feindt, U.; Fleury, M.; Gall, E.; Gonzalez-Gaitan, S.; Galbany, L.; Morales Garoffolo, A.; Greggio, L.; Guillou, L.L.; Hachinger, S.; Hadjiyska, E.; Hage, P.E.; Hillebrandt, W.; Hodgkin, S.; Hsiao, E.Y.; James, P.A.; Jerkstrand, A.; Kangas, T.; Kankare, E.; Kotak, R.; Kromer, M.; Kuncarayakti, H.; Leloudas, G.; Lundqvist, P.; Lyman, J.D.; Hook, I.M.; Maguire, K.; Manulis, I.; Margheim, S.J.; Mattila, S.; Maund, J.R.; Mazzali, P.A.; McCrum, M.; McKinnon, R.; Moreno-Raya, M.E.; Nicholl, M.; Nugent, P.; Pain, R.; Pignata, G.; Phillips, M.M.; Polshaw, J.; Pumo, M.; Rabinowitz, D.; Reilly, E.; Romero-Cañizales, C.; Scalzo, R.; Schmidt, B.; Schulze, S.; Sim, S.; Sollerman, J.; Taddia, F.; Tartaglia, L.; Terreran, G.; Tomasella, L.; Turatto, M.; Walker, E.; Walton, N.A.; Wyrzykowski, L.; Yuan, F.; Zampieri, L.Context. The Public European Southern Observatory Spectroscopic Survey of Transient Objects (PESSTO) began as a public spectroscopic survey in April 2012. PESSTO classifies transients from publicly available sources and wide-field surveys, and selects science targets for detailed spectroscopic and photometric follow-up. PESSTO runs for nine months of the year, January - April and August - December inclusive, and typically has allocations of 10 nights per month. Aims. We describe the data reduction strategy and data products that are publicly available through the ESO archive as the Spectroscopic Survey data release 1 (SSDR1). Methods. PESSTO uses the New Technology Telescope with the instruments EFOSC2 and SOFI to provide optical and NIR spectroscopy and imaging. We target supernovae and optical transients brighter than 20.5m for classification. Science targets are selected for follow-up based on the PESSTO science goal of extending knowledge of the extremes of the supernova population. We use standard EFOSC2 set-ups providing spectra with resolutions of 13-18 Å between 3345-9995 Å. A subset of the brighter science targets are selected for SOFI spectroscopy with the blue and red grisms (0.935-2.53 μm and resolutions 23-33 Å) and imaging with broadband JHKs filters. Results. This first data release (SSDR1) contains flux calibrated spectra from the first year (April 2012-2013). A total of 221 confirmed supernovae were classified, and we released calibrated optical spectra and classifications publicly within 24 h of the data being taken (via WISeREP). The data in SSDR1 replace those released spectra. They have more reliable and quantifiable flux calibrations, correction for telluric absorption, and are made available in standard ESO Phase 3 formats. We estimate the absolute accuracy of the flux calibrations for EFOSC2 across the whole survey in SSDR1 to be typically ∼15%, although a number of spectra will have less reliable absolute flux calibration because of weather and slit losses. Acquisition images for each spectrum are available which, in principle, can allow the user to refine the absolute flux calibration. The standard NIR reduction process does not produce high accuracy absolute spectrophotometry but synthetic photometry with accompanying JHKs imaging can improve this. Whenever possible, reduced SOFI images are provided to allow this. Conclusions. Future data releases will focus on improving the automated flux calibration of the data products. The rapid turnaround between discovery and classification and access to reliable pipeline processed data products has allowed early science papers in the first few months of the survey. © ESO, 2015.Ítem SN 2012ec: Mass of the progenitor from PESSTO follow-up of the photospheric phase(Oxford University Press, 2015-04) Barbarino, C.; Dall'Ora, M.; Botticella, M.T.; Della Valle, M.; Zampieri, L.; Maund, J.R.; Pumo, M.L.; Jerkstrand, A.; Benetti, S.; Elias-Rosa, N.; Fraser, M.; Gal-Yam, A.; Hamuy, M.; Inserra, C.; Knapic, C.; LaCluyze, A.P.; Molinaro, M.; Ochner, P.; Pastorello, A.; Pignata, G.; Reichart, D.E.; Ries, C.; Riffeser, A.; Schmidt, B.; Schmidt, M.; Smareglia, R.; Smartt, S.J.; Smith, K.; Sollerman, J.; Sullivan, M.; Tomasella, L.; Turatto, M.; Valenti, S.; Yaron, O.; Young, D.We present the results of a photometric and spectroscopic monitoring campaign of SN 2012ec, which exploded in the spiral galaxy NGC 1084, during the photospheric phase. The photometric light curve exhibits a plateau with luminosity L = 0.9 × 1042 erg s-1 and duration ~90 d, which is somewhat shorter than standard Type II-P supernovae (SNe). We estimate the nickel mass M(56Ni) = 0.040 ± 0.015 M⊙ from the luminosity at the beginning of the radioactive tail of the light curve. The explosion parameters of SN 2012ec were estimated from the comparison of the bolometric light curve and the observed temperature and velocity evolution of the ejecta with predictions from hydrodynamical models.We derived an envelope mass of 12.6 M⊙, an initial progenitor radius of 1.6 × 1013 cm and an explosion energy of 1.2 foe. These estimates agree with an independent study of the progenitor star identified in pre-explosion images, for which an initial mass ofM = 14-22 M⊙ was determined.We have applied the same analysis to two other Type II-P SNe (SNe 2012aw and 2012A), and carried out a comparison with the properties of SN 2012ec derived in this paper.We find a reasonable agreement between the masses of the progenitors obtained from pre-explosion images and masses derived from hydrodynamical models. We estimate the distance to SN 2012ec with the standardized candle method (SCM) and compare it with other estimates based on other primary and secondary indicators. SNe 2012A, 2012aw and 2012ec all follow the standard relations for the SCM for the use of Type II-P SNe as distance indicators. © 2015 The Authors.Ítem The type IIP supernova 2012aw in m95: Hydrodynamical modeling of the photospheric phase from accurate spectrophotometric monitoring(Institute of Physics Publishing, 2014-06) Dall'Ora, M.; Botticella, M.T.; Pumo, M.L.; Zampieri, L.; Tomasella, L.; Pignata, G.; Bayless, A.J.; Pritchard, T.A.; Taubenberger, S.; Kotak, R.; Inserra, C.; Della Valle, M.; Cappellaro, E.; Benetti, S.; Benitez, S.; Bufano, F.; Elias-Rosa, N.; Fraser, M.; Haislip, J.B.; Harutyunyan, A.; Howell, D.A.; Hsiao, E.Y.; Iijima, T.; Kankare, E.; Kuin, P.; Maund, J.R.; Morales-Garoffolo, A.; Morrell, N.; Munari, U.; Ochner, P.; Pastorello, A.; Patat, F.; Phillips, M.M.; Reichart, D.; Roming, P.W.A.; Siviero, A.; Smartt, S.J.; Sollerman, J.; Taddia, F.; Valenti, S.; Wright, D.We present an extensive optical and near-infrared photometric and spectroscopic campaign of the Type IIP supernova SN 2012aw. The data set densely covers the evolution of SN 2012aw shortly after the explosion through the end of the photospheric phase, with two additional photometric observations collected during the nebular phase, to fit the radioactive tail and estimate the 56Ni mass. Also included in our analysis is the previously published Swift UV data, therefore providing a complete view of the ultraviolet-optical-infrared evolution of the photospheric phase. On the basis of our data set, we estimate all the relevant physical parameters of SN 2012aw with our radiation-hydrodynamics code: envelope mass Menv ∼ 20 M , progenitor radius R ∼ 3 × 1013 cm (∼430 R ), explosion energy E ∼ 1.5 foe, and initial 56Ni mass ∼0.06 M . These mass and radius values are reasonably well supported by independent evolutionary models of the progenitor, and may suggest a progenitor mass higher than the observational limit of 16.5 ± 1.5 M of the Type IIP events.