During the last years, a number of telescopes have been dedicated to the followup of the GRBs. But after the Swift launch, the average observed intensity of the GRBs showed to be lower than thought ...before. Our experience with the robotic 60 cm REM telescope confirmed this evidence, with a large number of lost GRBs. Then, we proposed to study the feasibility of a 4 m fast pointing class telescope, equipped with a multichannel imagers, from Visible to Near Infrared. In this paper, we present the main result of the feasibility study we performed so far.
Closing gaps to our origins Gómez de Castro, Ana I; Barstow, Martin A.; Baudin, Frederic ...
Experimental astronomy,
12/2022, Letnik:
54, Številka:
2-3
Journal Article, Web Resource
Recenzirano
Odprti dostop
This article reproduces the contents of the White Paper entitled by the same name submitted to the call issued by the European Space Agency soliciting ideas from the scientific community for the ...science themes that should be covered during the Voyage 2050 planning cycle. This contribution focus in the investigation of the emergence of life and the role that astronomy has to play in it. Three fundamental areas of activity are identified: 1 measuring the chemical enrichment of the Universe, 2 investigating planet formation and searching for exoplanets with signatures of life and, 3 determining the abundance of amino acids and the chemical routes to amino acid and protein growth in astronomical bodies. This proposal deals with the first two. The building blocks of life in the Universe began as primordial gas processed in stars and mixed at galactic scales. The mechanisms responsible for this development are not well-understood and have changed over the intervening 13 billion years. To follow the evolution of matter over cosmic time, it is necessary to study the strongest (resonance) transitions of the most abundant species in the Universe. Most of them are in the ultraviolet (UV; 950 Å - 3000 Å ) spectral range that is unobservable from the ground; the “missing” metals problem cannot be addressed without this access. Habitable planets grow in protostellar discs under ultraviolet irradiation, a by-product of the accretion process that drives the physical and chemical evolution of discs and young planetary systems. The electronic transitions of the most abundant molecules are pumped by this UV field that is the main oxidizing agent in the disc chemistry and provides unique diagnostics of the planet-forming environment that cannot be accessed from the ground. Knowledge of the variability of the UV radiation field is required for the astrochemical modelling of protoplanetary discs, to understand the formation of planetary atmospheres and the photochemistry of the precursors of life. Earth’s atmosphere is in constant interaction with the interplanetary medium and the solar UV radiation field. The exosphere of the Earth extends up to 35 planetary radii providing an amazing wealth of information on our planet’s winds and the atmospheric compounds. To access to it in other planetary systems, observation of the UV resonance transitions is required. The investigation for the emergence of life calls for the development of large astronomical facilities, including instrumentation in optical and UV wavelengths. In this contribution, the need to develop a large observatory in the optical and in the UV is revealed, in order to complete the scientific goals to investigate the origin of life, inaccessible through other frequencies in the electromagnetic spectrum.
SN 2017dio shows both spectral characteristics of a type-Ic supernova (SN) and signs of a hydrogen-rich circumstellar medium (CSM). Prominent, narrow emission lines of H and He are superposed on the ...continuum. Subsequent evolution revealed that the SN ejecta are interacting with the CSM. The initial SN Ic identification was confirmed by removing the CSM interaction component from the spectrum and comparing with known SNe Ic and, reversely, adding a CSM interaction component to the spectra of known SNe Ic and comparing them to SN 2017dio. Excellent agreement was obtained with both procedures, reinforcing the SN Ic classification. The light curve constrains the pre-interaction SN Ic peak absolute magnitude to be around M g = − 17.6 mag. No evidence of significant extinction is found, ruling out a brighter luminosity required by an SN Ia classification. These pieces of evidence support the view that SN 2017dio is an SN Ic, and therefore the first firm case of an SN Ic with signatures of hydrogen-rich CSM in the early spectrum. The CSM is unlikely to have been shaped by steady-state stellar winds. The mass loss of the progenitor star must have been intense, M ˙ ∼ 0.02 ( ϵ H 0.01 ) − 1 ( v wind 500 km s−1) ( v shock 10,000 km s−1)−3 M yr−1, peaking at a few decades before the SN. Such a high mass-loss rate might have been experienced by the progenitor through eruptions or binary stripping.
Hubble Space Telescope and ground-based observations of the Type IIn supernova (SN) 2010jl are analyzed, including photometry and spectroscopy in the ultraviolet, optical, and near-IR bands, 26-1128 ...days after first detection. At maximum, the bolometric luminosity was ~3 x 10 super(43) erg s super(-1) and even at 850 days exceeds 10 super(42) erg s super(-1). A near-IR excess, dominating after 400 days, probably originates in dust in the circumstellar medium (CSM). The total radiated energy is > ~6.5 x 10 super(50) erg, excluding the dust component. The spectral lines can be separated into one broad component that is due to electron scattering and one narrow with expansion velocity ~100 km s super(-1) from the CSM. The broad component is initially symmetric around zero velocity but becomes blueshifted after ~50 days, while remaining symmetric about a shifted centroid velocity. Dust absorption in the ejecta is unlikely to explain the line shifts, and we attribute the shift instead to acceleration by the SN radiation. From the optical lines and the X-ray and dust properties, there is strong evidence for large-scale asymmetries in the CSM. The ultraviolet lines indicate CNO processing in the progenitor, while the optical shows a number of narrow coronal lines excited by the X-rays. The bolometric light curve is consistent with a radiative shock in an r super(-2) CSM with a mass-loss rate of M ~ 0.1 M sub(middot in circle) yr super(-1) The total mass lost is > ~3 M sub(middot in circle). These properties are consistent with the SN expanding into a CSM characteristic of a luminous blue variable progenitor with a bipolar geometry. The apparent absence of nuclear processing is attributed to a CSM that is still opaque to electron scattering.
SN 2008gz - most likely a normal Type IIP event Roy, Rupak; Kumar, Brijesh; Moskvitin, Alexander S ...
Monthly notices of the Royal Astronomical Society,
June 2011, Letnik:
414, Številka:
1
Journal Article
Recenzirano
We present BVRI photometric and low-resolution spectroscopic investigation of the Type II core-collapse supernova (SN) 2008gz, which occurred in a star-forming arm and within a half-light radius ...(solar metallicity region) of the nearby spiral galaxy NGC 3672. The SN event was detected late, and a detailed investigation of its light curves and spectra spanning 200 d suggest that it is an event of Type IIP similar to the archetypal SNe 2004et and 1999em. However, in contrast to other events of its class, SN 2008gz exhibits a rarely observed V magnitude drop of 1.5 over the period of a month during the plateau to nebular phase. Using an AV
of 0.21 mag as a lower limit and a distance of 25.5 Mpc, we estimate a synthesized 56Ni mass of 0.05 ± 0.01 M⊙, a mid-plateau MV
of −16.6 ± 0.2 mag and a total radiant energy of ∼1049 erg. The photospheric velocity is observed to be higher than observed for SN 2004et at similar epochs, indicating that the explosion energy was comparable to or higher than that of SN 2004et. A similar trend was also seen for the expansion velocity of H envelopes. By comparing the properties of SN 2008gz with other well-studied events, as well as by using a recent simulation of pre-SN models by Dessart, Livne & Waldman, we infer an explosion energy range of 2-3 × 1051 erg, and this coupled with the observed width of the forbidden O i 6300-6364 Å line at 275 d after the explosion gives an upper limit for the main-sequence (non-rotating, solar metallicity) progenitor mass of 17 M⊙. Our narrow-band Hα observation, taken nearly 560 d after the explosion, and the presence of an emission kink at zero velocity in the Doppler-corrected spectra of SN indicate that the event took place in a low-luminosity star-forming H ii region.
A common explosion mechanism for type la supernovae MAZZALI, Paolo A; RÖPKE, Friedrich K; BENETTI, Stefano ...
Science (American Association for the Advancement of Science),
2007, Letnik:
315, Številka:
5813
Journal Article
PDF
