18 research outputs found
GW190521: First Measurement of Stimulated Hawking Radiation from Black Holes
Being the most massive binary black hole merger event observed to date, GW190521 is in a class of its own. The exceptionally loud ringdown of this merger makes it an ideal candidate to search for gravitational wave echoes, a proposed smoking gun for the quantum structure of black hole horizons. We perform an unprecedented multi-pronged search for echoes via two well-established and independent pipelines: a template-based search for stimulated emission of Hawking radiation, or Boltzmann echoes, and the model-agnostic coherent WaveBurst (cWB) search. Stimulated Hawking radiation from the merger is expected to lead to post-merger echoes at horizon mode frequency of Hz (for quadrupolar gravitational radiation), repeating at intervals of second, due to partial reflection off Planckian quantum structure of the horizon. A careful analysis using dynamic nested sampling yields a Bayesian evidence of (90% confidence level) for this signal following GW190521, carrying an excess of in gravitational wave energy, relative to the main event. Similarly, the reconstructed waveform of the first echo in cWB carries an energy excess of . Accounting for the "look-elsewhere" effects, we estimate a p-value for false detection probability of (or 2.6) using cWB pipeline, although the verdict on the co-localization of the post-merger echo and the main event in the sky is inconclusive. While the current evidence for stimulated Hawking radiation does not reach the gold standard of , our findings are in line with expectations for stimulated Hawking radiation at current detector sensitivities. The next generation of gravitational wave observatories can thus draw a definitive conclusion on the quantum nature of black hole horizons
Bipolar ionization cones in the extended narrow-line region of nearby QSO2s
We have used narrowband [O III] λλ4959, 5007 and Hα+[N II] λλ6548, 84 Hubble Space Telescope (HST) images of nine luminous (L[O III]>1042 erg s−1) type 2 QSOs with redshifts 0.1<z<0.5 in order to constrain the geometry of their extended narrow-line regions (ENLRs), as recent ground-based studies suggest that these regions become more spherical at high luminosities due to destruction of the torus. We instead find elongated ENLRs reaching 4–19 kpc from the nucleus and bipolar ionization cones in [O III]/(Hα+[N II]) excitation maps indicating that the torus survives these luminosities, allowing the escape of ≈10 times higher ionizing photon rates along the ionization axis than perpendicular to it. The exceptional HST angular resolution was key to our success in arriving at these conclusions. Combining our measurements with previous ones based on similar HST data, we have revisited the relation between the ENLR radius Rmaj and L[O III] over the range 39<log(L[O III])<43.5 (L in erg s−1): log(Rmaj)=(0.51±0.03) log(L[O III]) −18.12±0.98. The radius of the ENLR keeps increasing with L[O III] in our data, implying that the ENLR can extend to distances beyond the limit of the galaxy if gas is present there—e.g., from active galactic nucleus (AGN) outflows or interactions, seen in six objects of our sample. We attribute the flattening previously seen in this relation to the fact that the ENLR is matter-bounded, meaning that ionizing photons usually escape to the intergalactic medium in luminous AGNs. Estimated ionized gas masses of the ENLRs range from 0.3 to 2×108Me, and estimated powers for associated outflows range from <0.1% to a few percent of the QSO luminosity
ATLANTIC BIRDS: a data set of bird species from the Brazilian Atlantic Forest
South America holds 30% of the world's avifauna, with the Atlantic Forest representing one of the richest regions of the Neotropics. Here we have compiled a data set on Brazilian Atlantic Forest bird occurrence (150,423) and abundance samples (N = 832 bird species; 33,119 bird individuals) using multiple methods, including qualitative surveys, mist nets, point counts, and line transects). We used four main sources of data: museum collections, on-line databases, literature sources, and unpublished reports. The data set comprises 4,122 localities and data from 1815 to 2017. Most studies were conducted in the Florestas de Interior (1,510 localities) and Serra do Mar (1,280 localities) biogeographic sub-regions. Considering the three main quantitative methods (mist net, point count, and line transect), we compiled abundance data for 745 species in 576 communities. In the data set, the most frequent species were Basileuterus culicivorus, Cyclaris gujanensis, and Conophaga lineata. There were 71 singletons, such as Lipaugus conditus and Calyptura cristata. We suggest that this small number of records reinforces the critical situation of these taxa in the Atlantic Forest. The information provided in this data set can be used for macroecological studies and to foster conservation strategies in this biodiversity hotspot. No copyright restrictions are associated with the data set. Please cite this Data Paper if data are used in publications and teaching events. © 2017 by the Ecological Society of Americ
Frequency and clinical correlates of bipolar features in acute coronary syndrome patients
Depression and acute coronary syndrome (ACS) are both extremely prevalent diseases. Studies aimed at evaluating whether depression is an independent risk factor for cardiac events provided no definitive results. In most of these studies, depression has been broadly defined with no differentiation between unipolar (MDD) versus bipolar forms (BD). The aim of this study was to evaluate the frequency of DSM-IV BD (bipolar I and bipolar II subtypes, cyclothymia), as well as temperamental or isolated bipolar features in a sample of 171 patients hospitalized for ACS. We also explored whether these psychopathological conditions were associated with some clinical characteristics of ACS
ACUTE CORONARY SYNDROMES AND DEPRESSION: ROLE OF CIRCULATING ENDOTHELIAL PROGENITOR CELLS
abstract non disponibil
Bipolar ionization cones in the extended narrow-line region of nearby QSO2s
We have used narrowband [O III] λλ4959, 5007 and Hα+[N II] λλ6548, 84 Hubble Space Telescope (HST) images of nine luminous (L[O III]>1042 erg s−1) type 2 QSOs with redshifts 0.1<z<0.5 in order to constrain the geometry of their extended narrow-line regions (ENLRs), as recent ground-based studies suggest that these regions become more spherical at high luminosities due to destruction of the torus. We instead find elongated ENLRs reaching 4–19 kpc from the nucleus and bipolar ionization cones in [O III]/(Hα+[N II]) excitation maps indicating that the torus survives these luminosities, allowing the escape of ≈10 times higher ionizing photon rates along the ionization axis than perpendicular to it. The exceptional HST angular resolution was key to our success in arriving at these conclusions. Combining our measurements with previous ones based on similar HST data, we have revisited the relation between the ENLR radius Rmaj and L[O III] over the range 39<log(L[O III])<43.5 (L in erg s−1): log(Rmaj)=(0.51±0.03) log(L[O III]) −18.12±0.98. The radius of the ENLR keeps increasing with L[O III] in our data, implying that the ENLR can extend to distances beyond the limit of the galaxy if gas is present there—e.g., from active galactic nucleus (AGN) outflows or interactions, seen in six objects of our sample. We attribute the flattening previously seen in this relation to the fact that the ENLR is matter-bounded, meaning that ionizing photons usually escape to the intergalactic medium in luminous AGNs. Estimated ionized gas masses of the ENLRs range from 0.3 to 2×108Me, and estimated powers for associated outflows range from <0.1% to a few percent of the QSO luminosity
Identification of Priority Conservation Areas and Potential Corridors for Jaguars in the Caatinga Biome, Brazil
ATLANTIC BIRDS: a data set of bird species from the Brazilian Atlantic Forest
South America holds 30% of the world's avifauna, with the Atlantic Forest representing one of the richest regions of the Neotropics. Here we have compiled a data set on Brazilian Atlantic Forest bird occurrence (150,423) and abundance samples (N = 832 bird species; 33,119 bird individuals) using multiple methods, including qualitative surveys, mist nets, point counts, and line transects). We used four main sources of data: museum collections, on-line databases, literature sources, and unpublished reports. The data set comprises 4,122 localities and data from 1815 to 2017. Most studies were conducted in the Florestas de Interior (1,510 localities) and Serra do Mar (1,280 localities) biogeographic sub-regions. Considering the three main quantitative methods (mist net, point count, and line transect), we compiled abundance data for 745 species in 576 communities. In the data set, the most frequent species were Basileuterus culicivorus, Cyclaris gujanensis, and Conophaga lineata. There were 71 singletons, such as Lipaugus conditus and Calyptura cristata. We suggest that this small number of records reinforces the critical situation of these taxa in the Atlantic Forest. The information provided in this data set can be used for macroecological studies and to foster conservation strategies in this biodiversity hotspot. No copyright restrictions are associated with the data set. Please cite this Data Paper if data are used in publications and teaching events. © 2017 by the Ecological Society of Americ