The X-ray evolution and geometry of the > 2018 outburst of XTE J1810-197

After 15 years, in late 2018, the magnetar XTE J1810–197 underwent a second recorded X-ray outburst event and reactivated as a radio pulsar. We initiated an Xray monitoring campaign to follow the timing and spectral evolution of the magnetar as its flux decays using Swift, XMM–Newton, NuSTAR, and NICER observations. During the year-long campaign, the magnetar reproduced similar behaviour to that found for the first outburst, with a factor of two change in its spin-down rate from ∼ 7.2 × 10−12 s s−1 to ∼ 1.5 × 10−11 s s−1 after two months. Unique to this outburst, we confirm the peculiar energy-dependent phase shift of the pulse profile. Following the initial outburst, the spectrum of XTE J1810–197 is well-modelled by multiple blackbody components corresponding to a pair of non-concentric, hot thermal caps surrounded by a cooler one, superposed to the colder star surface. We model the energy-dependent pulse profile to constrain the viewing and surface emission geometry and find that the overall geometry of XTE J1810–197 has likely evolved relative to that found for the 2003 event

Gemini Near Infrared Spectrograph Distant Quasar Survey: Initial Results

We present the first installment of spectroscopic measurements performed with the Gemini Near Infrared Spectrograph Distant Quasar Survey (GNIRS-DQS). This is a three-year project, launched in 2017, aimed at obtaining high quality near-infrared spectroscopy of 416 Sloan Digital Sky Survey (SDSS) quasars between redshifts of 1.5 and 3.5 in the ~1.0-2.5 μm band. A combination of the GNIRS and SDSS spectra will cover principal quasar diagnostic features, chiefly the C IV, Mg II, Hβ, and [O III] emission lines, in each source. The spectral inventory will be utilized primarily to develop prescriptions for obtaining more accurate and precise redshifts, black hole masses, and accretion rates for all quasars. Additionally, our measurements will facilitate a more complete understanding of how the rest-frame UV-optical spectral properties of quasars depend on redshift and luminosity, and test whether the physical properties of the quasar central engine evolve over cosmic time. Our raw data are immediately available to the public through the Gemini Observatory Archive, and our final reduced and calibrated spectra will be made available shortly thereafter on a dedicated public website. This work is supported by National Science Foundation grants AST-1815281 and AST-1815645.Fil: Matthews, Brandon. University of North Texas; Estados UnidosFil: Shemmer, Ohad. University of North Texas; Estados UnidosFil: Brotherton, Michael S.. University of North Texas; Estados UnidosFil: Andruchow, Ileana. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Boronson, Todd A.. Las Cumbres Observatory; ChileFil: Brandt, W. N.. State University of Pennsylvania; Estados UnidosFil: Cellone, Sergio Aldo. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Ferrero Sosa, Gabriel Antonio. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: and other authors. no específica; Argentina235th Meeting of the American Astronomical SocietySeattleEstados UnidosAmerican Astronomical Societ

A multimodal cell census and atlas of the mammalian primary motor cortex

ABSTRACT We report the generation of a multimodal cell census and atlas of the mammalian primary motor cortex (MOp or M1) as the initial product of the BRAIN Initiative Cell Census Network (BICCN). This was achieved by coordinated large-scale analyses of single-cell transcriptomes, chromatin accessibility, DNA methylomes, spatially resolved single-cell transcriptomes, morphological and electrophysiological properties, and cellular resolution input-output mapping, integrated through cross-modal computational analysis. Together, our results advance the collective knowledge and understanding of brain cell type organization: First, our study reveals a unified molecular genetic landscape of cortical cell types that congruently integrates their transcriptome, open chromatin and DNA methylation maps. Second, cross-species analysis achieves a unified taxonomy of transcriptomic types and their hierarchical organization that are conserved from mouse to marmoset and human. Third, cross-modal analysis provides compelling evidence for the epigenomic, transcriptomic, and gene regulatory basis of neuronal phenotypes such as their physiological and anatomical properties, demonstrating the biological validity and genomic underpinning of neuron types and subtypes. Fourth, in situ single-cell transcriptomics provides a spatially-resolved cell type atlas of the motor cortex. Fifth, integrated transcriptomic, epigenomic and anatomical analyses reveal the correspondence between neural circuits and transcriptomic cell types. We further present an extensive genetic toolset for targeting and fate mapping glutamatergic projection neuron types toward linking their developmental trajectory to their circuit function. Together, our results establish a unified and mechanistic framework of neuronal cell type organization that integrates multi-layered molecular genetic and spatial information with multi-faceted phenotypic properties