7 research outputs found
Distance determination to 12 Type II-P Supernovae using the Expanding Photosphere Method
We use early-time photometry and spectroscopy of 12 Type II plateau
supernovae (SNe IIP) to derive their distances using the expanding photosphere
method (EPM). We perform this study using two sets of Type II supernova (SN II)
atmosphere models, three filter subsets (, , ), and
two methods for the host-galaxy extinction, which leads to 12 Hubble diagrams.
We find that systematic differences in the atmosphere models lead to 50%
differences in the EPM distances and to a value of between 52 and
101 . Using the filter subset we obtain the
lowest dispersion in the Hubble diagram, { mag}. We
also apply the EPM analysis to the well-observed SN IIP 1999em. With the
filter subset we derive a distance ranging from 9.3 0.5 Mpc to
13.9 1.4 Mpc depending on the atmosphere model employed.Comment: Accepted for publication in the Astrophysical Journa
Improved Standardization of Type II-P Supernovae: Application to an Expanded Sample
In the epoch of precise and accurate cosmology, cross-confirmation using a
variety of cosmographic methods is paramount to circumvent systematic
uncertainties. Owing to progenitor histories and explosion physics differing
from those of Type Ia SNe (SNe Ia), Type II-plateau supernovae (SNe II-P) are
unlikely to be affected by evolution in the same way. Based on a new analysis
of 17 SNe II-P, and on an improved methodology, we find that SNe II-P are good
standardizable candles, almost comparable to SNe Ia. We derive a tight Hubble
diagram with a dispersion of 10% in distance, using the simple correlation
between luminosity and photospheric velocity introduced by Hamuy & Pinto 2002.
We show that the descendent method of Nugent et al. 2006 can be further
simplified and that the correction for dust extinction has low statistical
impact. We find that our SN sample favors, on average, a very steep dust law
with total to selective extinction R_V<2. Such an extinction law has been
recently inferred for many SNe Ia. Our results indicate that a distance
measurement can be obtained with a single spectrum of a SN II-P during the
plateau phase combined with sparse photometric measurements.Comment: ApJ accepted version. Minor change
Supernovae 2016bdu and 2005gl, and their link with SN 2009ip-like transients: another piece of the puzzle
Supernova (SN) 2016bdu is an unusual transient resembling SN 2009ip. SN
2009ip-like events are characterized by a long-lasting phase of erratic
variability which ends with two luminous outbursts a few weeks apart. The
second outburst is significantly more luminous (about 3 mag) than the first. In
the case of SN 2016bdu, the first outburst (Event A) reached an absolute
magnitude M(r) ~ -15.3 mag, while the second one (Event B) occurred over one
month later and reached M(r) ~ -18 mag. By inspecting archival data, a faint
source at the position of SN 2016bdu is detectable several times in the past
few years. We interpret these detections as signatures of a phase of erratic
variability, similar to that experienced by SN 2009ip between 2008 and
mid-2012, and resembling the currently observed variability of the luminous
blue variable SN 2000ch in NGC 3432. Spectroscopic monitoring of SN 2016bdu
during the second peak initially shows features typical of a SN IIn. One month
after the Event B maximum, the spectra develop broad Balmer lines with P Cygni
profiles and broad metal features. At these late phases, the spectra resemble
those of a typical Type II SN. All members of this SN 2009ip-like group are
remarkably similar to the Type IIn SN 2005gl. For this object, the claim of a
terminal SN explosion is supported by the disappearance of the progenitor star.
The similarity with SN 2005gl suggests that all members of this family may
finally explode as genuine SNe, although the unequivocal detection of
nucleosynthesised elements in their nebular spectra is still missing.Comment: Submitted to MNRAS on April 10, 2017; re-submitted on June 23
including suggestions from the referee. 24 pages, 12 figures, 5 table
Supernovae 2016bdu and 2005gl, and their link with SN 2009ip-like transients: another piece of the puzzle
Supernova (SN) 2016bdu is an unusual transient resembling SN 2009ip. SN
2009ip-like events are characterized by a long-lasting phase of erratic
variability which ends with two luminous outbursts a few weeks apart.
The second outburst is significantly more luminous (about 3 mag) than
the first. In the case of SN 2016bdu, the first outburst (Event A)
reached an absolute magnitude M(r) ~ -15.3 mag, while the second one
(Event B) occurred over one month later and reached M(r) ~ -18 mag. By
inspecting archival data, a faint source at the position of SN 2016bdu
is detectable several times in the past few years. We interpret these
detections as signatures of a phase of erratic variability, similar to
that experienced by SN 2009ip between 2008 and mid-2012, and resembling
the currently observed variability of the luminous blue variable SN
2000ch in NGC 3432. Spectroscopic monitoring of SN 2016bdu during the
second peak initially shows features typical of a SN IIn. One month
after the Event B maximum, the spectra develop broad Balmer lines with P
Cygni profiles and broad metal features. At these late phases, the
spectra resemble those of a typical Type II SN. All members of this SN
2009ip-like group are remarkably similar to the Type IIn SN 2005gl. For
this object, the claim of a terminal SN explosion is supported by the
disappearance of the progenitor star. The similarity with SN 2005gl
suggests that all members of this family may finally explode as genuine
SNe, although the unequivocal detection of nucleosynthesised elements in
their nebular spectra is still missing.
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PROJET GALION. Gestion alternative de la pĂȘcherie chalutiĂšre du Golfe du Lion
AmĂ©liorer la gestion des ressources marines est donc un impĂ©ratif au maintien des entreprises de pĂȘche, câest pourquoi les pĂȘcheurs chalutiers du golfe du Lion ont lancĂ© lâinitiative du projet GALION pour permettre de dĂ©finir de nouveaux modes de gestion pour cette pĂȘcherie. Le projet intĂšgre plusieurs phases de collecte de donnĂ©es en mer dans le cadre dâun partenariat entre scientifiques, pĂȘcheurs et Ă©conomistes. Plusieurs actions sont menĂ©es au cours des trois annĂ©es du projet :
1. Cartographier la distribution des captures et rejets. 2. DĂ©finir des habitats sensibles ou Ă risque. 3. Analyser la sĂ©lectivitĂ© des engins de pĂȘche et leur impact Ă©conomique. 4. Proposer des stratĂ©gies de pĂȘche limitant les rejets.
Ainsi le projet GALION vise Ă fournir aux pĂȘcheurs une aide Ă la dĂ©cision pour la meilleure stratĂ©gie de pĂȘche Ă adopter.
Ce projet est portĂ© par lâAMOP, en partenariat avec lâIfremer, le projet DISCARDLESS, le CĂ©pralmar, CapacitĂ©s Mer et SEANEO. Il a Ă©galement bĂ©nĂ©ficiĂ© des soutiens financiers de lâassociation France FiliĂšre PĂȘche, de la RĂ©gion Occitanie, de la RĂ©gion Provence Alpes CĂŽtes dâAzur, du Conseil DĂ©partemental du Gard et du Conseil DĂ©partemental de lâHĂ©rault