On the detection of TeV gamma-rays from GRB with km-cube neutrino telescopes --- I. Muon event rate from single GRBs

This is a preliminary study to examine the prospect of detecting TeV photons from $\gamma$-ray bursts (GRB) using km-size neutrino telescopes, specifically for the ANTARES neutrino telescope. Although optimized to detect upgoing neutrino-induced muons, neutrino telescopes nevertheless have a potential to detect high-energy photons by detecting downgoing muons from the electromagnetic cascade induced by the interaction of TeV photons with the Earth's atmosphere. The photon energy spectrum of a GRB is modeled by a simple power law and is normalized by simple energy considerations. Taking into account the absorption of TeV photons by cosmic infrared backgrounds, an optical depth table calculated from a model by \cite{fin10} is used and the arriving number of photons on top of the Earth atmosphere is determined. Muon production in the atmosphere is determined by considering two main channels of muon production: Pion photoproduction and direct muon pair production. The muon energy loss during their traverse from the surface to the bottom of the sea is determined using the standard muon energy loss formula. Assuming different detector sizes, the number of detectable muons from single GRB events located at different redshifts and zenith distances is determined. The background is calculated assuming it consists primarily of cosmic ray-induced downgoing muons. The detection significance is calculated and it can be concluded that to obtain at least $3\sigma$ detection significance, a typical GRB has to be located at redshift $z \lesssim 0.07$ if the detector's muon effective area is $A^{\mu}_{\rm eff} \sim 10^{-2}\;{\rm km}^{2}$, or redshift $z \lesssim 0.15$, if the muon effective area is $A^{\mu}_{\rm eff} \sim 1\;{\rm km}^{2}$.Comment: Thirteen pages, 14 figures. Accepted for publication in MNRA

Astrometric Constraints on the Masses of Long-period Gas Giant Planets in the TRAPPIST-1 Planetary System

We thank the David W. Thompson Family Fund for support of the CAPSCam astrometric planet search program, the Carnegie Observatories for continued access to the du Pont telescope, and the telescope operators and technicians at the Las Campanas Observatory for making these observations possible. We also thank the referee for several suggestions for improvements. The development of the CAPSCam camera was supported in part by NSF grant AST-0352912

Deep-Sea Bioluminescence Blooms after Dense Water Formation at the Ocean Surface

The deep ocean is the largest and least known ecosystem on Earth. It hosts numerous pelagic organisms, most of which are able to emit light. Here we present a unique data set consisting of a 2.5-year long record of light emission by deep-sea pelagic organisms, measured from December 2007 to June 2010 at the ANTARES underwater neutrino telescope in the deep NW Mediterranean Sea, jointly with synchronous hydrological records. This is the longest continuous time-series of deep-sea bioluminescence ever recorded. Our record reveals several weeks long, seasonal bioluminescence blooms with light intensity up to two orders of magnitude higher than background values, which correlate to changes in the properties of deep waters. Such changes are triggered by the winter cooling and evaporation experienced by the upper ocean layer in the Gulf of Lion that leads to the formation and subsequent sinking of dense water through a process known as “open-sea convection”. It episodically renews the deep water of the study area and conveys fresh organic matter that fuels the deep ecosystems. Luminous bacteria most likely are the main contributors to the observed deep-sea bioluminescence blooms. Our observations demonstrate a consistent and rapid connection between deep open-sea convection and bathypelagic biological activity, as expressed by bioluminescence. In a setting where dense water formation events are likely to decline under global warming scenarios enhancing ocean stratification, in situ observatories become essential as environmental sentinels for the monitoring and understanding of deep-sea ecosystem shifts

Deep-Sea Bioluminescence Blooms after Dense Water Formation at the Ocean Surface

<p>The deep ocean is the largest and least known ecosystem on Earth. It hosts numerous pelagic organisms, most of which are able to emit light. Here we present a unique data set consisting of a 2.5-year long record of light emission by deep-sea pelagic organisms, measured from December 2007 to June 2010 at the ANTARES underwater neutrino telescope in the deep NW Mediterranean Sea, jointly with synchronous hydrological records. This is the longest continuous time-series of deep-sea bioluminescence ever recorded. Our record reveals several weeks long, seasonal bioluminescence blooms with light intensity up to two orders of magnitude higher than background values, which correlate to changes in the properties of deep waters. Such changes are triggered by the winter cooling and evaporation experienced by the upper ocean layer in the Gulf of Lion that leads to the formation and subsequent sinking of dense water through a process known as "open-sea convection". It episodically renews the deep water of the study area and conveys fresh organic matter that fuels the deep ecosystems. Luminous bacteria most likely are the main contributors to the observed deep-sea bioluminescence blooms. Our observations demonstrate a consistent and rapid connection between deep open-sea convection and bathypelagic biological activity, as expressed by bioluminescence. In a setting where dense water formation events are likely to decline under global warming scenarios enhancing ocean stratification, in situ observatories become essential as environmental sentinels for the monitoring and understanding of deep-sea ecosystem shifts.</p>

Time series of oceanographic parameters measured at the Lacaze-Duthiers Canyon (LDC) and the open-sea convection region in the Gulf of Lion (LION) from January 2008 to June 2010.

<p>(<b>a</b>) Potential temperature at 500 and 1,000 m depth at the LDC mooring site and (<b>b</b>) from various water depths at the LION site, jointly with (<b>c</b>) salinity at 2,300 m depth, (<b>d</b>) horizontal current speed and (<b>e</b>) vertical current speed from various water depths at the LION site. The four levels of temperature measurements at LION presented here are a sub-set of measurement depths (see Fig. S1). Essentially stable temperatures in the deepest layers in 2008 show that open-sea convection reached only 700 m and did not modify the deep water in the study area. In contrast, strong convection events, reaching 2,300 m depth, occurred during February-March 2009 and 2010 with an abrupt cooling of the upper water column and an increase in temperature and salinity in the deep layers. A concurrent increase in current speed was also noticed in winter 2009 and 2010. The 5-month long data gap in 2009 is due to a damaging of the mooring line during the April 2009 recovery, which induced a postponement of its redeployment to September 2009.</p