Hasil untuk "astro-ph.HE"

M. Niyazi, M. Brada, A. Chalmers et al.

M. Tashiro, Rich Kelley, S. Watanabe et al.

The X-Ray Imaging and Spectroscopy Mission (XRISM) is a joint mission between the Japan Aerospace Exploration Agency (JAXA) and the National Aeronautics and Space Administration (NASA) in collaboration with the European Space Agency (ESA). In addition to the three space agencies, universities and research institutes from Japan, North America, and Europe have joined to contribute to developing satellite and onboard instruments, data-processing software, and the scientific observation program. XRISM is the successor to the ASTRO-H (Hitomi) mission, which ended prematurely in 2016. Its primary science goal is to examine astrophysical problems with precise, high-resolution X-ray spectroscopy. XRISM promises to discover new horizons in X-ray astronomy. It carries a 6 × 6 pixelized X-ray microcalorimeter on the focal plane of an X-ray mirror assembly (Resolve) and a co-aligned X-ray CCD camera (Xtend) that covers the same energy band over a large field of view. XRISM utilizes the Hitomi heritage, but all designs were reviewed. The attitude and orbit control system was improved in hardware and software. The spacecraft was launched from the JAXA Tanegashima Space Center on 2023 September 6 (UTC). During the in-orbit commissioning phase, the onboard components were activated. Although the gate valve protecting the Resolve sensor with a thin beryllium X-ray entrance window was not yet opened, scientific observation started in 2024 February with the planned performance verification observation program. The nominal observation program commenced with the following guest observation program beginning in 2024 September.

Y. Ishisaki, R. Kelley, H. Awaki et al.

Abstract. The Resolve instrument onboard the X-Ray Imaging and Spectroscopy Mission (XRISM) consists of an array of 6×6 silicon-thermistor microcalorimeters cooled down to 50 mK and a high-throughput X-ray mirror assembly (XMA) with a focal length of 5.6 m. XRISM is a recovery mission of ASTRO-H/Hitomi, and the Resolve instrument is a rebuild of the ASTRO-H Soft X-ray spectrometer (SXS) and the Soft X-ray Telescope (SXT) that achieved energy resolution of ∼5  eV FWHM on orbit, with several important changes based on lessons learned from ASTRO-H. The flight models of the Dewar and the electronics boxes were fabricated, and the instrument test and calibration were conducted in 2021. By tuning the cryocooler frequencies, energy resolution better than 4.9 eV FWHM at 6 keV was demonstrated for all 36 pixels and high-resolution grade events, as well as energy-scale accuracy better than 2 eV up to 30 keV. The immunity of the detectors to microvibration, electrical conduction, and radiation was evaluated. The instrument was delivered to the spacecraft system in April 2022. The XMA was tested and calibrated separately. Its angular resolution is 1.27′, and the effective area of the mirror itself is 570  cm2 at 1 keV and 424  cm2 at 6 keV. We report the design and the major changes from the ASTRO-H SXS, the integration, and the results of the instrument test.

I. C. M. Aartsen, M. Ackermann, J. Adams et al.

We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010 -- 2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated ($\sim 90 \%$) by electron and tau flavors. The flux, observed in the energy range from $16\,\mathrm{TeV} $ to $2.6\,\mathrm{PeV}$, is consistent with a single power-law as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be $\gamma=2.53\pm0.07$ and a flux normalization for each neutrino flavor of $\phi_{astro} = 1.66^{+0.25}_{-0.27}$ at $E_{0} = 100\, \mathrm{TeV}$. This flux of electron and tau neutrinos is in agreement with IceCube muon neutrino results and with all-neutrino flavor results. Results from fits assuming more complex neutrino flux models suggest a flux softening at high energies and a flux hardening at low energies (p-value $\ge 0.06$).

S. Juneau, A. Jacques, Steve Pothier et al.

SPectra Analysis and Retrievable Catalog Lab (SPARCL) at NOIRLab's Astro Data Lab was created to efficiently serve large optical and infrared spectroscopic datasets. It consists of services, tools, example workflows and currently contains spectra for over 7.5 million stars, galaxies and quasars from the Sloan Digital Sky Survey (SDSS) and the Dark Energy Spectroscopic Instrument (DESI) survey. We aim to eventually support the broad range of spectroscopic datasets that will be hosted at NOIRLab and beyond. Major elements of SPARCL include capabilities to discover and query for spectra based on parameters of interest, a fast web service that delivers desired spectra either individually or in bulk as well as documentation and example Jupyter Notebooks to empower users in their research. More information is available on the SPARCL website (https://astrosparcl.datalab.noirlab.edu).

Razmik Mirzoyan

The ground-based technique for imaging atmospheric Cherenkov telescopes became a rapidly developing and powerful branch of science. Thanks to this technique, over 250 very high-energy gamma-ray sources of galactic and extragalactic origin have been discovered. Many fundamental questions of astrophysics, astro-particle physics, the physics of cosmic rays and cosmology are the focus of this technique. In the past 33 years since the discovery of the first gamma-ray source, the Crab Nebula, the discipline has made remarkable progress. Today, the technology boasts highly sensitive telescopes capable of detecting a point source 100 times fainter than the standard candle, the Crab Nebula, in 25 hours of observation. Further developments in this technology led to the Cherenkov Telescope Array (CTA), the next-generation large instrument. The sensitivity of CTA will be several times higher than that of the current best instruments. This article presents a brief history of ground-based very high energy gamma-ray astrophysics.

Monica Seglar-Arroyo, Halim Ashkar, Mathieu de Bony de Lavergne et al.

Time-domain astrophysics has leaped forward with the direct discovery of gravitational waves and the emergence of new generation instruments for multi-messenger studies. The capacity of the multi-messenger multi-wavelength community to effectively pursue follow-up observations is hindered by the suboptimal localization of numerous transient events and the escalating volume of alerts. Thus, we have developed an effective tool to overcome the observational and technical hurdles inherent in the emerging field of multi-messenger astrophysics. We present tilepy, a Python package for the automatic scheduling of follow-up observations of poorly localized transient events. It is ideally suited to tackle the challenge of complex follow-up in mid and small-FoV telescope campaigns, with or without human intervention. We demonstrate the capabilities of tilepy in the realm of multi-observatory, multi-wavelength campaigns, to cover the localization uncertainty region of various events ultimately aiming at pinpointing the source of the multi-messenger emission. The tilepy code is publicly available on GitHub and is sufficiently flexible to be employed either automatically or in a customized manner, tailored to collaboration and individual requirements. tilepy is also accessible via a public API and through the Astro-COLIBRI platform.

S. Worrell, K. Goodman, Nasser K. Altorki et al.

Outcomes for patients with esophageal cancer have improved over the last decade with the implementation of multimodality therapy. There are currently no comprehensive guidelines addressing multidisciplinary management of esophageal cancer that have incorporated the input of surgeons, radiation oncologists, and medical oncologists. To address the need for multidisciplinary input in the management of esophageal cancer and to meet current best practices for clinical practice guidelines, the current guidelines were created as a collaboration between The Society of Thoracic Surgeons (STS), American Society for Radiation Oncology (ASTRO), and the American Society of Clinical Oncology (ASCO). Physician representatives chose 8 key clinical questions pertinent to the care of patients with locally advanced, resectable thoracic esophageal cancer (excluding cervical location). A comprehensive literature review was performed identifying 227 articles that met the inclusion criteria covering the use of induction chemotherapy, chemotherapy vs chemoradiotherapy before surgery, optimal radiation dose, the value of esophagectomy, timing of esophagectomy, the approach and extent of lymphadenectomy, the use of minimally invasive esophagectomy, and the value of adjuvant therapy after resection. The relevant data were reviewed and voted on by the panel with 80% of the authors, with 75% agreement on class and level of evidence. These data were then complied into the guidelines document.

A. Cabrera, J. Kirkpatrick, J. Fiveash et al.

B. Schneider, M. Daly, E. Kennedy et al.

G. Fastner, C. Gaisberger, J. Kaiser et al.

The aim of this review is to provide a comprehensive overview of the role of intraoperative radiation therapy with electrons (IOERT) in breast conserving therapy (BCT), both as partial breast irradiation (PBI) as well as anticipated boost ("IOERT-Boost"). For both applications, the criteria for patient selection, technical details/requirements, physical aspects and outcome data are presented. IOERT as PBI The largest evidence comes from Italian studies, especially the ELIOT randomized trial. Investigators showed that the rate of in-breast relapses (IBR) in the IOERT group was significantly greater than with whole breast irradiation (WBI), even when within the pre-specified equivalence margin. Tumour sizes > 2 cm, involved axillary nodes, Grade 3 and triple negative molecular subtypes emerged as statistically significant predictors of IBR. For patients at low risk for in-breast recurrence (ASTRO/ESTRO recommendations), full dose IOERT was isoeffective with standard WBI. Hence, several national guidelines now include this treatment strategy as one of the standard techniques for PBI in carefully selected patients. IOERT Boost The largest evidence for boost IOERT preceding WBI comes from pooled analyses performed by the European Group of the International Society of Intraoperative Radiation Therapy (ISIORT Europe), where single boost doses (mostly around 10 Gy) preceded whole-breast irradiation (WBI) with 50 Gy (conventional fractionation). At median follow-up periods up to ten years, local recurrence rates around 1% were observed for low risk tumours. Higher local relapse rates were described for grade 3 tumours, triple negative breast cancer as well as for patients treated after primary systemic therapy for locally advanced tumours. Even in this settings, long-term (> 5y) local tumour control rates beyond 95% were achieved. These encouraging results are interpreted as being attributable to utmost precision in dose delivery (by avoiding a "geographic and/or temporal miss"), and the possible radiobiological superiority of a single high dose fraction, compared to the conventionally fractionated boost. IOERT also showed favourable results in terms of cosmetic outcome, assumedly thanks to the small treated volumes combined with complete skin sparing.

Chih-Hao Li, A. Benedick, P. Fendel et al.

Searches for extrasolar planets using the periodic Doppler shift of stellar spectral lines have recently achieved a precision of 60 cm s-1 (ref. 1), which is sufficient to find a 5-Earth-mass planet in a Mercury-like orbit around a Sun-like star. To find a 1-Earth-mass planet in an Earth-like orbit, a precision of ∼5 cm s-1 is necessary. The combination of a laser frequency comb with a Fabry–Pérot filtering cavity has been suggested as a promising approach to achieve such Doppler shift resolution via improved spectrograph wavelength calibration, with recent encouraging results. Here we report the fabrication of such a filtered laser comb with up to 40-GHz (∼1-Å) line spacing, generated from a 1-GHz repetition-rate source, without compromising long-term stability, reproducibility or spectral resolution. This wide-line-spacing comb, or ‘astro-comb’, is well matched to the resolving power of high-resolution astrophysical spectrographs. The astro-comb should allow a precision as high as 1 cm s-1 in astronomical radial velocity measurements.

Laura Olivera-Nieto, Vikas Joshi, Harm Schoorlemmer et al.

A wide range of data formats and proprietary software have traditionally been used in gamma-ray astronomy, usually developed for a single specific mission or experiment. However, in recent years there has been an increasing effort towards making astronomical data open and easily accessible. Within the gamma-ray community this has translated to the creation of a common data format across different gamma-ray observatories: the "gamma-astro-data-format" (GADF). Based on a similar premise, open-source analysis packages, such as Gammapy, are being developed and aim to provide a single, robust tool which suits the needs of many experiments at once. In this contribution we show that data from the High-Altitude Water Cherenkov (HAWC) observatory can be made compatible with the GADF and present the first GADF-based production of event lists and instrument response functions for a ground-based wide-field instrument. We use these data products to reproduce with excellent agreement the published HAWC Crab spectrum using Gammapy. Having a common data format and analysis tools facilitates joint analysis between different experiments and effective data sharing. This will be especially important for next-generation instruments, such as the proposed Southern Wide-field Gamma-ray Observatory (SWGO) and the planned Cherenkov Telescope Array (CTA).

Gregory Ashton, Eric Thrane

The gravitational-wave candidate GW151216 is a proposed binary black hole event from the first observing run of the Advanced LIGO detectors. Not identified as a bona fide signal by the LIGO--Virgo collaboration, there is disagreement as to its authenticity, which is quantified by $p_\text{astro}$, the probability that the event is astrophysical in origin. Previous estimates of $p_\text{astro}$ from different groups range from 0.18 to 0.71, making it unclear whether this event should be included in population analyses, which typically require $p_\text{astro}>0.5$. Whether GW151216 is an astrophysical signal or not has implications for the population properties of stellar-mass black holes and hence the evolution of massive stars. Using the astrophysical odds, a Bayesian method which uses the signal coherence between detectors and a parameterised model of non-astrophysical detector noise, we find that $p_\text{astro}=0.03$, suggesting that GW151216 is unlikely to be a genuine signal. We also analyse GW150914 (the first gravitational-wave detection) and GW151012 (initially considered to be an ambiguous detection) and find $p_\text{astro}$ values of 1 and 0.997 respectively. We argue that the astrophysical odds presented here improve upon traditional methods for distinguishing signals from noise.

C. Amling, E. Bergstralh, M. Blute et al.

A. Bezjak, S. Temin, G. Franklin et al.

Barak Zackay, Tejaswi Venumadhav, Liang Dai et al.

We report a new binary black hole merger in the publicly available LIGO First Observing Run (O1) data release. The event has an inverse false alarm rate of one per six years in the detector-frame chirp-mass range $\mathcal{M}^{\rm det} \in [20,40]M_\odot$ in a new independent analysis pipeline that we developed. Our best estimate of the probability that the event is of astrophysical origin is $P_{\rm astro} \sim 0.71\, .$ The estimated physical parameters of the event indicate that it is the merger of two massive black holes, $\mathcal{M}^{\rm det} = 31^{+2}_{-3}\,M_\odot$ with an effective spin parameter, $χ_{\rm eff} = 0.81^{+0.15}_{-0.21}$, making this the most highly spinning merger reported to date. It is also among the two highest redshift mergers observed so far. The high aligned spin of the merger supports the hypothesis that merging binary black holes can be created by binary stellar evolution.

J. Craig Wheeler, József Vinkó, Rafaella Margutti et al.

The large aperture and sensitive optical and near infrared imager spectrographs will enable an ELT system to observe some supernovae at large distances, deep into cosmological history when supernovae first began to occur.

O. González-Martín

Scaling relations are the most powerful astrophysical tools to set constraints to the physical mechanisms of astro- nomical sources and to infer properties that cannot be accessed directly. We re-investigate here one of these scaling relations in active galactic nuclei (AGN); the so-called X-ray variability plane (or mass-luminosity-timescale relation, McHardy et al. 2006). This relation links the power-spectral density (PSD) break frequency with the super-massive black hole (SMBH) mass and the bolometric luminosity. We used available XMM -Newton observations of a sample of 22 AGN to study the PSD and spectra in short segments within each observation. This allows us to report for the first time that the PSD break frequency varies for each object, showing variations in 19 out of the 22 AGN analyzed. Our analysis of the variability plane confirms the relation between the break frequency and the SMBH mass and finds that the obscuration along the line of sight NH (or the variations on the obscuration using its standard deviation, $\rmΔ$(NH)) is also a required parameter, at least for the range of frequencies analyzed here (3x10E-5-5x10E-2Hz). We constrain a new variability plane of the form: log($ν_{Break}$) = (-0.589$\rm{\pm}$0.005) log(MBH ) + (0.10$\rm{\pm}$0.01) log(NH ) - (1.5$\rm{\pm}$0.3) (or log($ν_{Break}$)=(-0.549$\rm{\pm}$0.009)log(MBH)+(0.56$\rm{\pm}$0.06)$\rmΔ$(NH)+(0.19$\rm{\pm}$0.08)). The X-ray variability plane found by McHardy et al. (2006) is roughly recovered when we use unobscured segments. We speculate that this behavior is well explained if most of the reported frequencies are related to inner clouds (within 1pc), following Kepler orbits under the gravitational field of the SMBH.

S. Freedland, R. Rumble, A. Finelli et al.