A5024027946- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- SAS software applications and methods
- Pulsars and Gravitational Waves Research
- Atomic and Molecular Physics
- Adaptive optics and wavefront sensing
- Advanced Frequency and Time Standards
- Space Exploration and Technology
- Nuclear physics research studies
- Astrophysics and Cosmic Phenomena
- High-pressure geophysics and materials
- Atmospheric Ozone and Climate
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Spectroscopy and Laser Applications
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Nuclear Physics and Applications
- Molecular Spectroscopy and Structure
- Cold Atom Physics and Bose-Einstein Condensates
Telescopio Nazionale Galileo
2008-2023
National Institute for Astrophysics
2005-2020
IAC (United States)
2005-2010
Osservatorio Astrofisico di Catania
1983-2008
Thüringer Landessternwarte Tautenburg
2003
University of Hawaii–West Oahu
2003
Istituto Nazionale di Fisica Nucleare, Galileo Galilei Institute for Theoretical Physics
2002
Casa di Cura Città di Roma
1994-1995
Byurakan Astrophysical Observatory
1993
Instituto de Astrofísica de Canarias
1991
view Abstract Citations (223) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Spectroscopy of a Brown Dwarf Candidate in the alpha Persei Open Cluster Rebolo, Rafael ; Martin, Eduardo L. Magazzu, Antonio Intermediate-resolution spectroscopy range 625-775 nm is reported for faint very-late-type object discovered two CCD images taken near center Alpha Per cluster. The spectrum shows strong absorption molecular bands, H-alpha emission, and KI...
We report the discovery of 76 new T dwarfs from UKIDSS Large Area Survey (LAS). Near-infrared broad and narrow-band photometry spectroscopy are presented for objects, along with WISE warm-Spitzer photometry. Proper motions 128 a two epoch LAS proper motion catalogue. use these to identify benchmark systems: LHS 6176AB, T8+M4 pair HD118865AB, T5.5+F8 pair. Using age constraints primaries evolutionary models constrain radii we have estimated their physical properties bolometric luminosity....
We present the first detection of atomic emission lines from atmosphere an exoplanet. detect neutral iron day-side KELT-9b (Teq $\sim$ 4, 000 K). combined thousands spectrally resolved observed during one night with HARPS-N spectrograph (R 115, 000), mounted at Telescopio Nazionale Galileo. introduce a novel statistical approach to extract planetary parameters binary mask cross-correlation analysis. also adapt concept contribution function context high spectral resolution observations,...
We present the confirmation of two new planets transiting nearby mid-M dwarf LTT 3780 (TIC 36724087, TOI-732, $V=13.07$, $K_s=8.204$, $R_s$=0.374 R$_{\odot}$, $M_s$=0.401 M$_{\odot}$, d=22 pc). The planet candidates are identified in a single TESS sector and validated with reconnaissance spectroscopy, ground-based photometric follow-up, high-resolution imaging. With measured orbital periods $P_b=0.77$ days, $P_c=12.25$ days sizes $r_{p,b}=1.33\pm 0.07$ R$_{\oplus}$, $r_{p,c}=2.30\pm 0.16$...
We report the discovery of three very late T dwarfs in UKIRT Infrared Deep Sky Survey (UKIDSS) Third Data Release: ULAS J101721.40+011817.9 (ULAS1017), J123828.51+095351.3 (ULAS1238) and J133553.45+113005.2 (ULAS1335). detail optical near-infrared (NIR) photometry for all sources, mid-IR ULAS1335. use NIR spectra each source to assign spectral types T8p T8.5 T9 (ULAS1335) these objects. ULAS1017 is classed as a peculiar T8 (T8p) due appearing dwarf J band, whilst exhibiting H- K-band flux...
We present the discovery of optical transient long-duration gamma-ray burst GRB 000630. The was detected with Nordic Optical Telescope 21.1 hours after burst. At time magnitude . displayed a power-law decline characterized by decay slope A deep image obtained 25 days shows no indication contribution from supernova or host galaxy at position transient. closest is 2.0 arcsec north magnitudes afterglows 980329, 980613 and 000630 were all less than 24 epoch. discuss implications this for our...
We have identified four brown dwarfs in the Taurus star-forming region. They were first selected from $R$ and $I$ CCD photometry of 2.29 square degrees obtained at Canada-France-Hawaii Telescope. Subsequently, they recovered 2MASS second incremental data release point source catalog. Low-resolution optical spectra William Herschel telescope allow us to derive spectral types range M7--M9. One has very strong H$\alpha$ emission (EW=-340 \AA). It also displays Br$\gamma$ an infrared spectrum...
view Abstract Citations (127) References (30) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Spectroscopic Test for Substellar Objects Magazzu, Antonio ; Martin, Eduardo L. Rebolo, Rafael We describe a spectroscopic test capable of providing direct confirmation the substellar nature brown dwarf candidates. While conditions substantial lithium burning are reached even in very low-mass stars, objects with less than 0.06 solar mass such never attained and Li...
We present the discovery of fifteen new T2.5-T7.5 dwarfs (with estimated distances between ~24-93pc, identified in first three main data releases UKIRT Infrared Deep Sky Survey. This brings total number T discovered Large Area Survey (to date) to 28. These discoveries are confirmed by near infrared spectroscopy, from which we derive spectral types on unified scheme Burgasser et al. (2006). Seven have T2.5-T4.5, five T5-T5.5, one is a T6.5p, and two T7-7.5. assess morphology colours identify...
We present eight new T4.5-T7.5 dwarfs identified in the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area (LAS) Data Release 1 (DR1). In addition we have recovered T4.5 dwarf SDSS J020742.91+000056.2 and T8.5 ULAS J003402.77-005206.7. Photometric candidates were picked up two-colour diagrams over 190 square degrees (DR1) selected at least two filters. All exhibit near-infrared spectra with strong methane water absorption bands characteristic of T derived spectral types follow unified scheme...
Observations of the extraordinarily bright optical afterglow (OA) GRB 991208 started 2.1 d after event. The flux decay constant OA in R-band is -2.30 +/- 0.07 up to 5 d, which very likely due jet effect, and that it followed by a much steeper with -3.2 0.2, fastest one ever seen OA. A negative detection several all-sky films taken simultaneously event implies either previous additional break prior 2 occurrence (as expected from effect). existence second might indicate steepening electron...
Aims: Low-resolution optical spectroscopic observations for 78 very low-mass star and brown dwarf candidates that have been photometrically selected using the DENIS survey point source catalogue. Methods: Spectral types are derived them measurements of PC3 index. They range from M6 to L4. H_alpha emission NaI subordinate doublet (818.3 nm 819.9 nm) equivalent widths measured in spectra. Spectroscopic indices TiO, VO, CrH FeH molecular features also reported. Results: A rule-of-thumb...
view Abstract Citations (97) References (57) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Lithium Abundances in Classical and Weak T Tauri Stars Magazzu, Antonio ; Rebolo, Rafael Pavlenko, Iakov V. A study on the lithium abundance 36 stars (mass range 0.4-2.25 solar masses), partly based high-dispersion spectra taken with Isaac Newton Telescope, is presented. of non-LTE effects formation double derived corrections to abundances LTE 1.0-4.0 log N(Li) Tor...
Extensive optical and near-infrared observations of the Type Ib supernova (SNIb) 1999dn are presented, covering first year after explosion. These new data turn this object, already considered a prototypical SNIb, into one best observed objects its class. The light curve SN is mostly similar in shape to that other SNeIb but with moderately faint peak (MV=−17.2 mag). From bolometric ejecta expansion velocities, we estimate about 0.11 M⊙ 56Ni were produced during explosion total mass was 4–6...
Context. Young stars and multi-planet systems are two types of primary objects that allow us to study, understand, constrain planetary formation evolution theories. Aims. We validate the physical nature Neptune-sized planets transiting TOI-942 (TYC 5909-319-1), a previously unacknowledged young star (50 −20 +30 Myr) observed by TESS space mission in Sector 5. Methods. Thanks comprehensive stellar characterization, light curve modeling precise radial-velocity measurements, we validated...
We present complete near-infrared (0.85-2.45 μm), low-resolution (~100) spectra of a sample 26 disk L dwarfs with reliable optical spectral type classification. The observations have been obtained the Near Infrared Camera and Spectrograph at Telescopio Nazionale Galileo using prism-based element (the Amici device) that provides spectrum source on detector. Our show spectroscopy can be used to determine classification in fast but accurate way. library as templates for faint dwarfs. also...
We present intermediate and low resolution optical spectroscopy (650-915 nm) of seven faint, very red objects (20 > I >= 17.8, I-Z 0.5) discovered in a CCD-based IZ survey covering an area 1 sq. deg the central region Pleiades open cluster. The observed spectra show that these are cool dwarfs, having spectral types range M6-M9. Five out can be considered as members on basis their radial velocities, Halpha emission other gravity sensitive atomic features like NaI doublet at 818.3 819.5...
The GRB010222 optical and near-infrared (NIR) afterglow was monitored at the TNG other Italian telescopes starting ∼1 day after high-energy prompt event.The BV R light curves, which are best sampled, continuously steepening can be described by two power laws, f (t) ∝ t -α , of indices α1 ∼ 0.7 α2 1.3 before a break occurring about 0.5 days GRB start time, respectively.This model accounts well also for flux in U I J bands, less monitored.The temporal appears to achromatic.The K-band points...
Aims.We have investigated the structure of pulsating atmosphere one best studied rapidly oscillating Ap stars, HD 24712.
We report near-infrared and optical follow-up observations of the afterglow GRB 000418 starting 2.5 days after occurrence burst extending over nearly 7 weeks. represents second case for which was initially identified by in near-infrared. During first 10 its R-band well characterized a single power-law decay with slope 0.86. However, at later times temporal evolution flattens respect to simple decay. Attributing this an underlying host galaxy, we find magnitude be R = 23.9 intrinsic 1.22. The...
view Abstract Citations (75) References (33) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Constraints to the Masses of Brown Dwarf Candidates from Lithium Test Martin, Eduardo L. ; Rebolo, Rafael Magazzu, Antonio We present intermediate dispersion (0.7-2.2 Å~pix$^{-1}$) optical spectroscopic observations aimed at applying ``Lithium Test'' a sample ten brown dwarf candidates located in general field, two young open clusters, and close binaries. find...
Aims.Spectroscopic monitoring of BL Lac objects is a difficult task that nonetheless can provide important information on the different components active galactic nucleus.
To date, only 18 exoplanets with radial velocity (RV) semi-amplitudes $<2$ m/s have had their masses directly constrained. The biggest obstacle to RV detection of such is variability intrinsic stars themselves, e.g. nuisance signals arising from surface magnetic activity as rotating spots and plages, which can drown out or even mimic planetary signals. We use Kepler-37 - known host three transiting planets, one which, Kepler-37d, should be on the cusp detectability modern spectrographs a...
K2-136 is a late-K dwarf ($0.742\pm0.039$ M$_\odot$) in the Hyades open cluster with three known, transiting planets and an age of $650\pm70$ Myr. Analyzing K2 photometry, we found that K2-136b, c, d have periods $8.0$, $17.3$, $25.6$ days radii $1.014\pm0.050$ R$_\oplus$, $3.00\pm0.13$ $1.565\pm0.077$ respectively. We collected 93 radial velocity measurements (RVs) HARPS-N spectrograph (TNG) 22 RVs ESPRESSO (VLT). data jointly, K2-136c induced semi-amplitude $5.49\pm0.53$ m s$^{-1}$,...