Optical-NIR spectroscopy of the puzzling gamma-ray source 3FGL 1603.9-4903/PMN J1603-4904 with X-shooter

The Fermi/LAT instrument has detected about two thousands Extragalactic High Energy (E > 100 MeV) gamma-ray sources. One of the brightest is 3FGL 1603.9-4903, associated to the radio source PMN J1603-4904. Its nature is not yet clear, it could be either a very peculiar BL Lac or a CSO (Compact Symmetric Object) radio source, considered as the early stage of a radio galaxy. The latter, if confirmed, would be the first detection in gamma-rays for this class of objects. Recently a redshift z=0.18 +/- 0.01 has been claimed on the basis of the detection of a single X-ray line at 5.44 +/- 0.05 keV interpreted as a 6.4 keV (rest frame) fluorescent line. We aim to investigate the nature of 3FGL 1603.9-4903/PMN J1603-4904 using optical to NIR spectroscopy. We observed PMN J1603-4904 with the UV-NIR VLT/X-shooter spectrograph for two hours. We extracted spectra in the VIS and NIR range that we calibrated in flux and corrected for telluric absorption and we systematically searched for absorption and emission features. The source was detected starting from ~6300 Ang down to 24000 Ang with an intensity comparable to the one of its 2MASS counterpart and a mostly featureless spectrum. The continuum lacks absorption features and thus is non-stellar in origin and likely non-thermal. On top of this spectrum we detected three emission lines that we interpret as the Halpha-[NII] complex, the [SII] 6716,6731 doublet and the [SIII] 9530 line, obtaining a redshift estimate of z= 0.2321 +/- 0.0004. The equivalent width of the Halpha-[NII] complex implies that PMN J1603-4904 does not follow the observational definition of BL Lac, the line ratios suggest that a LINER/Seyfert nucleus is powering the emission. This new redshift measurement implies that the X-ray line previously detected should be interpreted as a 6.7 keV line which is very peculiar.Comment: Published in Astronomy and Astrophysic

Aerial imaging of fluorescent dye in the near shore

Author Posting. © American Meteorological Society, 2014. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 31 (2014): 1410–1421, doi:10.1175/JTECH-D-13-00230.1.Aerial images are used to quantify the concentration of fluorescent Rhodamine water tracing (WT) dye in turbid and optically deep water. Tracer releases near the shoreline of an ocean beach and near a tidal inlet were observed with a two-band multispectral camera and a pushbroom hyperspectral imager, respectively. The aerial observations are compared with near-surface in situ measurements. The ratio of upwelling radiance near the Rhodamine WT excitation and emission peaks varies linearly with the in situ dye concentrations for concentrations <20 ppb (r2 = 0.70 and r2 = 0.85–0.88 at the beach and inlet, respectively). The linear relationship allows for relative tracer concentration estimates without in situ calibration. The O(1 m) image pixels resolve complex flow structures on the inner shelf that transport and mix tracer.We thank ONR and NSF for funding this work.2014-12-0

Autophagy-mediated degradation of nuclear envelope proteins during oncogene-induced senescence

Here, we report that nuclear envelope proteins are subjected to autophagic proteolysis in human cells undergoing oncogene-induced senescence. This degradation occurs in parallel with autophagy and lysosomal activity induction that accompanies the establishment of the senescence respons

Discovery of VHE gamma-rays from RGB J0152+017

The BL Lac object RGB J0152+017 (z = 0.080) was predicted to be a very high-energy (VHE; > 100 GeV) gamma-ray source, due to its high X-ray and radio fluxes. We report recent observations of this source made in late October and November 2007 with the H.E.S.S. array consisting of four imaging atmospheric Cerenkov telescopes. Contemporaneous observations were made in X-rays with the Swift and RXTE satellites, in the optical band with the ATOM telescope, and in the radio band with the Nancay Radio Telescope. As a result, RGB J0152+017 is discovered as a source of VHE gamma-rays by H.E.S.S. A signal of 173 gamma-ray photons corresponding to a statistical significance of 6.6 sigmas was found in the data. The energy spectrum of the source can be described by a powerlaw with a spectral index of = 2.95 +- 0.36stat +- 0.20syst. The integral flux above 300 GeV corresponds to ~2% of the flux of the Crab nebula. The source spectral energy distribution (SED) can be described using a two-component (extended jet and blob in jet) non-thermal synchrotron self-Compton (SSC) leptonic model, plus a thermal host galaxy component. The parameters that are found are very close to those found for TeV blazars in similar SSC studies. The location of its synchrotron peak, as derived from the SED in Swift data, allows clear classification as a high-frequency-peaked BL Lac (HBL).Comment: 6 pages, 5 figures; accepted to appear in the proceedings of the Workshop on Blazar Variability across the Electromagnetic Spectrum, 22-25 April 2008, Palaiseau, Franc

Phonological Features for 0-shot Multilingual Speech Synthesis

Code-switching---the intra-utterance use of multiple languages---is prevalent across the world. Within text-to-speech (TTS), multilingual models have been found to enable code-switching. By modifying the linguistic input to sequence-to-sequence TTS, we show that code-switching is possible for languages unseen during training, even within monolingual models. We use a small set of phonological features derived from the International Phonetic Alphabet (IPA), such as vowel height and frontness, consonant place and manner. This allows the model topology to stay unchanged for different languages, and enables new, previously unseen feature combinations to be interpreted by the model. We show that this allows us to generate intelligible, code-switched speech in a new language at test time, including the approximation of sounds never seen in training.Comment: 5 pages, to be presented at INTERSPEECH 202

Autophagy-mediated degradation of nuclear envelope proteins during oncogene-induced senescence.

Cellular senescence is a largely irreversible form of cell cycle arrest triggered by various types of damage and stress, including oncogene expression (termed oncogene-induced senescence or OIS). We and others have previously demonstrated that OIS occurs in human benign lesions, acting as a potent tumor suppressor mechanism. Numerous phenotypic changes occur during OIS, both in the cytoplasm and in the nucleus. These include the activation of autophagy, a catabolic process operating in the cytoplasm and downregulation of lamin B1, a component of the nuclear lamina. However, it is unknown whether these changes relate to each other. We discovered that cells entering BRAF(V600E)- or H-RAS(G12V)-induced senescence downregulate not only lamin B1 but also lamin A, as well as several other nuclear envelope (NE) proteins, resulting in an altered NE morphology. Depletion of LMNB1 or LMNA/C was sufficient to recapitulate some OIS features, including cell cycle exit and downregulation of NE proteins. We further found that the global loss of NE proteins is a consequence of their degradation by the autophagy machinery, which occurs concomitantly with autophagy induction and increased lysosomal content and activity. Our study therefore reveals a previously unknown connection between autophagy and the disruption of NE integrity during OIS

Progress in Monte Carlo design and optimization of the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) will be an instrument covering a wide energy range in very-high-energy (VHE) gamma rays. CTA will include several types of telescopes, in order to optimize the performance over the whole energy range. Both large-scale Monte Carlo (MC) simulations of CTA super-sets (including many different possible CTA layouts as sub-sets) and smaller-scale simulations dedicated to individual aspects were carried out and are on-going. We summarize results of the prior round of large-scale simulations, show where the design has now evolved beyond the conservative assumptions of the prior round and present first results from the on-going new round of MC simulations.Comment: 4 pages, 5 figures. In Proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), Rio de Janeiro (Brazil). All CTA contributions at arXiv:1307.223

A Two Zone Synchrotron Model for the Knots in the M87 Jet

The flux and the spectral index in X-ray energy band from the knots of M87 jet as observed by {\it{Chandra}} indicate a possible synchrotron origin but cannot be explained by simple one zone models with continuous injection of non-thermal electrons. In this letter we propose a two-zone model to explain the observed spectra of the knots of M87 jet. We consider the synchrotron emission from a region with tangled magnetic field where relativistic non-thermal electrons are continuously injected in from an associated acceleration region. The acceleration region is assumed to be compact zone possibly around a shock front. A power-law distribution of electron is injected into the acceleration region and are accelerated to a maximum energy determined by the acceleration time scale and the loss processes. With the present model we are able to explain the overall broadband features of the knots of M87 jet. Also the present model predicts a change in spectral index at ultraviolet energies and future observations at these energies can be used to constrain the parameters involved in the model.Comment: 5 pages, 1 figure, typos correcte