Accurate Hijri Calculator 2.2 Sebagai Piranti Hisab Penentuan Awal Bulan Hijriah Berdasarkan Kriteria Visibilitas Hilal Nasional Dan Internasional

Perhitungan dan observasi untuk penentuan awal bulan Hijriah dalam penanggalan Islam adalah permasalahan krusial yang dihadapi oleh umat Islam setiap tahun. Dalam penelitian ini, telah dikembangkan software yang dinamakan Accurate Hijri Calculator 2.2 (AHC) sebagai alat bantu dalam perhitungan penentuan awal bulan Hijriah. Metode pelaksanaan dalam penelitian ini terdiri dari pembuatan software, pengumpulan data hisab dan rukyat, metode wawancara, dan verifikasi hasil perhitungan software dengan data hisab dan rukyat. Data-data hisab dikumpulkan dari hasil perhitungan software USNO dan Accurate Time 5.3.4 sedangkan data rukyat dikumpulkan dari Kementerian Agama RI dan Moonsighting Committee Worlwide (moonsighting.com). Metode verifikasi dilakukan dengan membandingkan beberapa hasil perhitungan software AHC dengan data hisab dan membandingkan hasil perhitungan prediksi kenampakan hilal dengan data rukyat. Software AHC mempunyai banyak aplikasi diantaranya: dapat menghitung koordinat bulan dan matahari, mengkonversi penanggalan Masehi (Gregorian) ke dalam penanggalan Hijriah, memprediksi kenampakan hilal untuk lokasi-lokasi di seluruh dunia dalam bentuk peta visibilitas hilal, dan menghitung semua parameter dalam penentuan awal bulan Muharram, Ramadhan, Syawwal, dan Dzulhijjah. Software ini mengakomodir berbagai kriteria penanggalan hijriah yang digunakan di Indonesia maupun Internasional. Dari hasil verifikasi didapatkan bahwa perhitungan software AHC cukup akurat

A closer look at the host-galaxy environment of high-velocity Type Ia supernovae

Recent studies suggested that the ejecta velocity of Type Ia supernova (SN Ia) is a promising indicator in distinguishing the progenitor systems and explosion mechanisms. By classifying the SNe Ia based on their ejecta velocities, studies found SNe Ia with high Si II $\lambda$6355 velocities (HV SNe Ia; v>12000 km/s) tend to be physically different from their normal-velocity counterparts (NV SNe Ia). In this work, we revisit the low-$z$ sample studied in previous work and closely look into the spatially resolved environment local to the site of SN explosion. Our results reveal a possible trend (at $2.4\sigma$ significance) that HV SNe Ia are likely associated with older stellar populations than NV SNe Ia. While the trend is inconclusive, the local host-galaxy sample studied in this work is likely skewed toward massive galaxies, limiting the parameter space that we would like to investigate from the original parent sample. Nevertheless, our results do not rule out the possibility that parameters other than the host-galaxy age (such as metallicity) could be the underlying factors driving the differences between HV and NV SNe Ia due to the limitation of our dataset.Comment: 13 pages, 6 figures, accepted for publication in MNRA

JWST/NIRCam probes young star clusters in the reionization era sunrise arc

This work is based on observations made with the NASA/ ESA/CSA James Webb Space Telescope (JWST) and Hubble Space Telescope (HST). These observations are associated with JWST GO program 2282 and HST GO programs 14096, 15842, and 16668. The data (doi:10.17909/cqfq-5n80) were obtained from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contractNAS 5-03127 for JWST. We acknowledge financial support from NASA through grant JWST-GO-02282. We thank the anonymous referee for the constructive comments. A.A. acknowledges support from the Swedish Research Council (Vetenskapsrådet project grant 2021-05559). A.A. and A.C. thank M. Messa for sharing an earlier version of his software. E.V. acknowledges financial support through grants PRIN-MIUR 2017WSCC32 and 2020SKSTHZ and INAF “main-stream” grants 1.05.01.86.20 and 1.05.01.86.31. We acknowledge support from INAF GO grant 2022, “The revolution is around the corner: JWST will probe globular cluster precursors and Population III stellar clusters at cosmic dawn” (PI: Vanzella). J.M.D. acknowledges the support of projects PGC2018-101814-B-100 and MDM-2017-0765. M.B. acknowledges support from the Slovenian national research agency ARRS through grant N1-0238. P.D. acknowledges support from NWO grant 016.VIDI.189.162 (“ODIN”) and the European Commission’s and University of Groningen’s COFUND Rosalind Franklin program. M.O. acknowledges support from JSPS KAKENHI grant Nos. JP22H01260, JP20H05856, and JP20H00181. S.F. acknowledges support from NASA through NASA Hubble Fellowship grant HSTHF2-51505.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. B.W. acknowledges support from NASA under award No. 80GSFC21M0002. L.J.F. and A.Z. acknowledge support by grant No. 2020750 from the United States–Israel Binational Science Foundation (BSF), grant No. 2109066 from the United States National Science Foundation (NSF), and the Ministry of Science & Technology, Israel. E.V. thanks the colleague Antonio Sollima for inspiring discussions on local stellar clusters; Antonio, unfortunately, passed away prematurely at the age of 43, during the acceptance of this work

Extreme damped Lyman-α\alpha absorption in young star-forming galaxies at z=9−11z=9-11

The onset of galaxy formation is thought to be initiated by the infall of neutral, pristine gas onto the first protogalactic halos. However, direct constraints on the abundance of neutral atomic hydrogen (HI) in galaxies have been difficult to obtain at early cosmic times. Here we present spectroscopic observations with JWST of three galaxies at redshifts $z=8.8 - 11.4$, about $400-600$ Myr after the Big Bang, that show strong damped Lyman-$\alpha$ absorption ($N_{\rm HI} > 10^{22}$ cm$^{-2}$) from HI in their local surroundings, an order of magnitude in excess of the Lyman-$\alpha$ absorption caused by the neutral intergalactic medium at these redshifts. Consequently, these early galaxies cannot be contributing significantly to reionization, at least at their current evolutionary stages. Simulations of galaxy formation show that such massive gas reservoirs surrounding young galaxies so early in the history of the universe is a signature of galaxy formation in progress.Comment: Submitte

Two Lensed Star Candidates at z ≃ 4.8 behind the Galaxy Cluster MACS J0647.7+7015

We report the discovery of two extremely magnified lensed star candidates behind the galaxy cluster MACS J0647.7+015 using recent multiband James Webb Space Telescope (JWST) NIRCam observations. The star candidates are seen in a previously known, zphot ≃ 4.8 dropout giant arc that straddles the critical curve. The candidates lie near the expected critical curve position, but lack clear counter-images on the other side of it, suggesting these are possibly stars undergoing caustic crossings. We present revised lensing models for the cluster, including multiply imaged galaxies newly identified in the JWST data, and use them to estimate background macro-magnifications of at least ≳90 and ≳50 at the positions of the two candidates, respectively. With these values, we expect effective, caustic-crossing magnifications of ∼[103–105] for the two star candidates. The spectral energy distributions of the two candidates match well the spectra of B-type stars with best-fit surface temperatures of ∼10,000 K, and ∼12,000 K, respectively, and we show that such stars with masses ≳20 M⊙ and ≳50 M⊙, respectively, can become sufficiently magnified to be observable. We briefly discuss other alternative explanations and conclude that these objects are likely lensed stars, but also acknowledge that the less-magnified candidate may alternatively reside in a star cluster. These star candidates constitute the second highest-redshift examples to date after Earendel at zphot ≃ 6.2, establishing further the potential of studying extremely magnified stars at high redshifts with JWST. Planned future observations, including with NIRSpec, will enable a more detailed view of these candidates in the near future.A.K.M., A.Z., and L.J.F. acknowledge support from grant 2020750 from the United States-Israel Binational Science Foundation (BSF) and grant 2109066 from the United States National Science Foundation (NSF), and by the Ministry of Science & Technology, Israel. Y.J.-T. acknowledges financial support from the European Unionʼs Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 898633, the MSCA IF Extensions Program of the Spanish National Research Council (CSIC), and the State Agency for Research of the Spanish MCIU through the Center of Excellence Severo Ochoa award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). E.Z. acknowl edges funding from the Swedish National Space Agency. J.M. D. acknowledges the support of projects PGC2018-101814-B 100 and MDM-2017-0765. B.W. acknowledges support from NASA under award No. 80GSFC21M0002. A.A. acknowledges support from the Swedish Research Council (Vetens kapsrådet project grants 2021–05559). R.A.B gratefully acknowledges support from the European Space Agency (ESA) Research Fellowship. M.B. acknowledges support from the Slovenian national research agency ARRS through grant N1-0238. P.D. acknowledges support from the NWO grant 016.VIDI.189.162 (“ODIN”) and from the European Commission’s and University of Groningen’s CO-FUND Rosalind Franklin program. G.M. acknowledges funding from the European Unionʼs Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. MARACHAS—DLV-896778. R.A.W. acknowledges support from NASA JWST Interdisciplinary Scientist grants NAG5-12460, NNX14AN10G and 80NSSC18K0200 from GSFC