21 research outputs found
Rapidly Rising Transients in the Supernova - Superluminous Supernova Gap
The American Astronomical Society. All rights reserved..We present observations of four rapidly rising (trise ≈ 10 days) transients with peak luminosities between those of supernovae (SNe) and superluminous SNe (Mpeak ap; -20) - one discovered and followed by the Palomar Transient Factory (PTF) and three by the Supernova Legacy Survey. The light curves resemble those of SN 2011kl, recently shown to be associated with an ultra-long-duration gamma-ray burst (GRB), though no GRB was seen to accompany our SNe. The rapid rise to a luminous peak places these events in a unique part of SN phase space, challenging standard SN emission mechanisms. Spectra of the PTF event formally classify it as an SN II due to broad Hα emission, but an unusual absorption feature, which can be interpreted as either high velocity Hα (though deeper than in previously known cases) or Si ii (as seen in SNe Ia), is also observed. We find that existing models of white dwarf detonations, CSM interaction, shock breakout in a wind (or steeper CSM), and magnetar spin down cannot readily explain the observations. We consider the possibility that a "Type 1.5 SN" scenario could be the origin of our events. More detailed models for these kinds of transients and more constraining observations of future such events should help to better determine their nature. © 2016
Diagnostic accuracy of F-18-FDG PET/CT and MR imaging in patients with adenoid cystic carcinoma
Contains fulltext :
181614.pdf (publisher's version ) (Open Access
The DESI One-Percent survey: exploring the Halo Occupation Distribution of Emission Line Galaxies with AbacusSummit simulations
International audienceThe One-Percent survey of the Dark Energy Spectroscopic Instrument collected ~ 270k emission line galaxies (ELGs) at 0.8 ~ 11.9. We obtain a satellite mean occupation function which agrees with physically motivated ELG models only if we introduce central-satellite conformity, meaning that the satellite occupation is conditioned by the presence of central galaxies of the same type. To achieve in addition a good modeling of the clustering between 0.1 and 1 Mpc/h in rp, we allow for ELG positioning outside of the halo virial radius and find 0.5% of ELGs residing in the outskirts of halos. Furthermore, the satellite velocity dispersion inside halos is found to be ~ 30% larger than that of the halo dark matter particles. These are the main findings of our work. We investigate assembly bias as a function of halo concentration, local density or local density anisotropies and observe no significant change in our results. We split the data sample in two redshift bins and report no significant evolution with redshift. Lastly, changing the cosmology in the modeling impacts only slightly our results
The DESI One-Percent survey: exploring the Halo Occupation Distribution of Emission Line Galaxies with AbacusSummit simulations
The One-Percent survey of the Dark Energy Spectroscopic Instrument collected
~ 270k emission line galaxies (ELGs) at 0.8 < z < 1.6. The high completeness of
the sample allowed the clustering to be measured down to scales never probed
before, 0.04 Mpc/h in rp for the projected 2-point correlation function (2PCF)
and 0.17 Mpc/h in galaxy pair separation s for the 2PCF monopole and
quadrupole. The most striking feature of the measurements is a strong signal at
the smallest scales, below 0.2 Mpc/h in rp and 1 Mpc/h in s. We analyze these
data in the halo occupation distribution framework. We consider different
distributions for central galaxies, a standard power law for satellites with no
condition on the presence of a central galaxy and explore several extensions of
these models. For all considered models, the mean halo mass of the sample is
found to be log10 ~ 11.9. We obtain a satellite mean occupation function
which agrees with physically motivated ELG models only if we introduce
central-satellite conformity, meaning that the satellite occupation is
conditioned by the presence of central galaxies of the same type. To achieve in
addition a good modeling of the clustering between 0.1 and 1 Mpc/h in rp, we
allow for ELG positioning outside of the halo virial radius and find 0.5% of
ELGs residing in the outskirts of halos. Furthermore, the satellite velocity
dispersion inside halos is found to be ~ 30% larger than that of the halo dark
matter particles. These are the main findings of our work. We investigate
assembly bias as a function of halo concentration, local density or local
density anisotropies and observe no significant change in our results. We split
the data sample in two redshift bins and report no significant evolution with
redshift. Lastly, changing the cosmology in the modeling impacts only slightly
our results