Journal of Astrophysics and Astronomy最新文献

{"title":"Indian spectroscopic and imaging space telescope (INSIST): An optics design trade-off study","authors":"S. Sriram,&nbsp;Vineeth Valsan,&nbsp;A. Subramaniam,&nbsp;C. Vishnu Unni,&nbsp;G. Maheswar,&nbsp;Totan Chand","doi":"10.1007/s12036-023-09934-y","DOIUrl":"10.1007/s12036-023-09934-y","url":null,"abstract":"<div><p>Large ground and space-based surveys in optical and near-infrared (NIR) wavelengths will revolutionize astronomy in the coming decade. Unfortunately, no ultraviolet (UV) facilities are planned to complement these surveys, which is crucial for studying the most active phase of the Universe that includes star formation in galaxies, active galactic nuclei (AGN), galaxy clusters, etc. A dedicated UV mission, the Indian Spectroscopic and Imaging Space Telescope (INSIST), is proposed to observe the UV sky. The compelling science objectives defined a set of high-level mission requirements. According to which, the INSIST is to have a wide field-of-view (<span>(textrm{FoV} approx 0.25)</span> square degree) comparable to India’s Ultraviolet Imaging Telescope (UVIT) and about two orders of magnitude larger than that of the Hubble Space Telescope, simultaneous imaging of the FoV in UV (150–300 nm), u (300–400 nm) and g (400–550 nm) bands, a Multi-Object-Slit medium resolution spectroscopy in a narrow FoV in UV and a simultaneous slitless spectroscopic capability in UV and u bands. To achieve these requirements, several optical design configurations were explored. Here, we present an optical design trade study conducted on various optical design configurations to achieve a sensitivity limit of <span>(m_{textrm{AB}}&gt; 26)</span> mag, in the UV band and a spatial resolution better than 0.2<span>(^{prime prime })</span>, using a 1-m size telescope aperture. We also present results from our fabrication and alignment tolerance analysis of the selected optical designs, and the design performance that meets the design requirements. Critical parameters like the encircled energy concentration, point spread function (its stability over the field), effects of the spiders supporting the secondary, etc., are explored during the design phase. Based on the trade study conducted in reference to various performance matrices, we down-selected the most optimal optical design for the INSIST.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12036-023-09934-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4346293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Near infrared background with 1.2-m telescope at Mount Abu","authors":"Prachi Prajapati,&nbsp;Anwesh Mishra,&nbsp;Ananya Rawat,&nbsp;Shashikiran Ganesh,&nbsp;Vishal Joshi,&nbsp;Navpreet Kaur,&nbsp;Neeraj Kumari,&nbsp;Sachindra Naik,&nbsp;Sunil Chandra","doi":"10.1007/s12036-023-09933-z","DOIUrl":"10.1007/s12036-023-09933-z","url":null,"abstract":"<div><p>We present an estimation and analysis of Near Infrared (NIR) background for the astronomical site at Mount Abu. Mount Abu Observatory is situated at Gurushikhar, Rajasthan, India, operated by the Physical Research Laboratory. Data obtained from the NIR observations of various sources using the Near Infrared Camera/Spectrograph (NICS) on the 1.2-m telescope are used to derive the NIR background estimates. We notice seasonal variations in these values, with the summer months showing brighter background compared to the winter. We also present a comparison of synthetic atmospheric transmission at Mount Abu with other Indian observatories at various altitudes. We identify the plausible contributors to the NIR background in our observations and discuss the potential ones that can contribute to the noticed seasonal variations. Overall, we found that the NIR background does not show any systematic variation over the period of observations from 2010 to 2019. The results reported here are specific to the NICS instrument on the 1.2-m telescope.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4627809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Far infrared properties of OH megamaser host galaxies","authors":"Jin Wang,&nbsp;Bu-Hui Lv,&nbsp;Ru-Qiu Lin,&nbsp;You-Xin Wang,&nbsp;Ye-Wei Mao,&nbsp;Hong-Zhi Yu,&nbsp;Ze-Yin Lv,&nbsp;Jia-Lu Qiu,&nbsp;Jiang-Shui Zhang,&nbsp;Qian Guo,&nbsp;Ming Liang","doi":"10.1007/s12036-023-09942-y","DOIUrl":"10.1007/s12036-023-09942-y","url":null,"abstract":"<div><p>The hosts of OH megamaser (OHM) are luminous infrared galaxies (LIRGs), in fact 1/3 of them are ultra-luminous infrared galaxies (ULIRGs), which imply that OHM phenomena should be related to the infrared radiation field. In this paper, we investigate the far infrared (FIR) properties of OHM host galaxies, through detailed infrared data covering broad bands. All known OHM sources and one control sample of (U)LIRGs without maser detections (non-OHM sources) are cross-identified with AKARI and Herschel photometric catalogs. Comparative analysis on the spectral energy distribution (SED) with broad coverage from <i>J</i> to 350 <span>(mu )</span>m (taken from 2MASS, WISE, Spitzer, and AKARI and Herschel archive data) shows that the OHM sources tend to have higher FIR luminosities than those of the non-OHM sources, which are more pronounced in the SED range covered by the AKARI. These are consistent with our statistical results of the FIR luminosities distribution of both the samples, which show that the OHM sources tend to have higher FIR luminosities, especially, at short FIR wavelength (i.e., the 65 and 90 <span>(mu )</span>m). However, the non-OHM sources tend to have much stronger emission than those of OHM sources at both the near infrared (NIR) and middle infrared (MIR) bands. The statistic analysis of the color–color properties at MIR and FIR bands shows that the OHM sources have much cooler MIR and warmer FIR colors than non-OHM sources. These clues could help us to choose OHM candidates for future OHM surveys with the Five-hundred-meter Aperture Spherical radio Telescope (FAST), where the OHM detection rate may exceed 40%. Further, one significant correlation of <span>(L_textrm{OH} propto L_{T_textrm{FIR}}^{1.18pm 0.11})</span> can be found between the maser luminosity and total FIR luminosity of OHM LIRGs. Combined with previous studies, we suggest that the OHM is dominantly pumped by the FIR, instead of NIR and MIR radiation fields.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4091351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TIRCAM2 fast sub-array readout mode for lunar occultation studies","authors":"Milind B. Naik,&nbsp;Devendra K. Ojha,&nbsp;Saurabh Sharma,&nbsp;Shailesh B. Bhagat,&nbsp;Savio L. D’costa,&nbsp;Arpan Ghosh,&nbsp;Koshvendra Singh","doi":"10.1007/s12036-023-09946-8","DOIUrl":"10.1007/s12036-023-09946-8","url":null,"abstract":"<div><p>TIFR Near Infrared Imaging Camera-II (TIRCAM2) is being used at the Devasthal Optical Telescope (DOT) operated by Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital, Uttarakhand, India. In addition to the normal full frame observations, there has been a requirement for high speed sub-array observations for applications, such as lunar occultation and star speckle observations. Fast sub-array modes have been implemented in TIRCAM2 with suitable changes in the camera software at the computer and controller DSP code level. Successful observations have been carried out with the fast sub-array mode of observation.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4066088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kronberger 55: A candidate for end-dominated collapse scenario","authors":"Aayushi Verma,&nbsp;Saurabh Sharma,&nbsp;Lokesh Dewangan,&nbsp;Rakesh Pandey,&nbsp;Tapas Baug,&nbsp;Devendra K. Ojha,&nbsp;Arpan Ghosh,&nbsp;Harmeen Kaur","doi":"10.1007/s12036-023-09932-0","DOIUrl":"10.1007/s12036-023-09932-0","url":null,"abstract":"<div><p>Using optical photometric observations from 1.3-m Devasthal Fast Optical Telescope and deep near-infrared (NIR) photometric observations from TANSPEC mounted on 3.6-m Devasthal Optical Telescope, along with the multi-wavelength archival data, we present our study of open cluster Kronberger 55 to understand the star-formation scenario in the region. The distance, extinction and age of the cluster Kronberger 55 are estimated as <span>(sim )</span>3.5 kpc, <span>(E(B-V)sim 1.0)</span> mag and <span>(lesssim )</span>5 Myr, respectively. We identified Young Stellar Objects (YSOs) based on their excess infrared (IR) emission using the two-color diagrams (TCDs). The mid-infrared (MIR) images reveal the presence of extended structure of dust and gas emission along with the outflow activities in the region with two peaks, one at the location of cluster Kronberger 55 and another at <span>(5^{prime }.35)</span> southwards to it. The association of radio continuum emission with the southern peak, hints towards the formation of massive star/s. The Herschel sub-millimeter maps reveal the presence of two clumps connected with a filamentary structure in this region, and such configuration is also evident in the <span>(^{12})</span>CO(1–0) emission map. Our study suggests that this region might be a hub-filament system undergoing star formation due to the ‘end-dominated collapse scenario’.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5183656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectroscopy of nine eruptive young variables using TANSPEC","authors":"Arpan Ghosh,&nbsp;Saurabh Sharma,&nbsp;Joe P. Ninan,&nbsp;Devendra K. Ojha,&nbsp;A. S. Gour,&nbsp;Rakesh Pandey,&nbsp;Tirthendu Sinha,&nbsp;Aayushi Verma,&nbsp;Koshvendra Singh,&nbsp;Supriyo Ghosh,&nbsp;Harmeen Kaur","doi":"10.1007/s12036-023-09939-7","DOIUrl":"10.1007/s12036-023-09939-7","url":null,"abstract":"<div><p>In recent times, 3.6m Devasthal Optical Telescope (DOT) has been installed with an optical to near infra-red spectrograph, TANSPEC, which provides spectral coverage from 0.55 to 2.5 microns. Using TANSPEC, we have obtained a single epoch spectrum of a set, containing nine FUors and EXors. We have analysed line profiles of the sources and compared them with the previously published spectra of these objects. Comparing the line profile shapes with the existing theoretical predictions, we have tried to interpret the physical processes that are responsible for the current disc evolution and the present accretion dynamics. Our study has shown the importance of time-evolved spectroscopic studies for a better understanding of the evolution of the accretion a mechanisms. This in turn can help in the better characterization of the young stars displaying episodic accretion behavior.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12036-023-09939-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5127402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of weak discontinuity waves in non-ideal interstellar environments","authors":"Shweta,&nbsp;Rahul Kumar Chaturvedi,&nbsp;Shobhit Kumar Srivastava,&nbsp;L. P. Singh","doi":"10.1007/s12036-023-09943-x","DOIUrl":"10.1007/s12036-023-09943-x","url":null,"abstract":"<div><p>A systematic method is used to study the problem of propagation of planar, cylindrically symmetric and spherically symmetric shock waves of the one-dimensional motion of an inviscid, self-gravitating, non-ideal interstellar gas cloud. The analytic solution of the problem is resolved, which specifies non-linear behavior in the physical plane. The transport equation, which describes the evolution of weak discontinuity in non-ideal gas is derived. It is observed that the nature of the solution completely depends on the net volumetric cooling rate and self-gravitating parameter. It is observed that an increase in the value of self-gravitating parameter results in delay of process of shock formation and shock forms early when heating dominates cooling in the system. Also, expansive waves take less time to decay in planar geometry as compared to cylindrical and spherical geometries and compressive waves take more time to develop shocks for cylindrical and spherical geometries as compared to planar geometry.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4799196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A long baseline tracking network for improved NavIC orbit determination","authors":"B. N. Ramakrishna,&nbsp;P. D. Mishra,&nbsp;T. Subramanya Ganesh,&nbsp;Sharda Vashisth,&nbsp;Amitava Sen Gupta","doi":"10.1007/s12036-023-09950-y","DOIUrl":"10.1007/s12036-023-09950-y","url":null,"abstract":"<div><p>Currently, the orbit determination accuracy of Navigation with Indian Constellation (NavIC) satellites is better than 20 m using the measurements from one-way ranging network of stations. The NavIC ephemerides along with time are continuously transmitted from the NavIC satellites. The transmitted ephemerides are also known as the broadcast ephemerides. These ephemerides are functions of precise orbit determination and dynamical model used for the orbit propagation and are one of the major error sources in the NavIC receiver position. In this paper, a study has been carried out to improve the orbit determination. This is performed through the precise orbit determination using extended tracking network with a sufficiently long baseline tracking stations (LBTS). We first attempted to fix a suitable number of LBTS based on several criteria, such as geometry, elevation cut-off angle, minimum tracking duration, etc. LBTS are optimally selected to reduce the along-track, in-track and cross-track errors in the estimated orbit. We also address the precise orbit determination of NavIC satellites by employing a weighed least square differential correction method. In the orbit determination process, the numerical integration orbit propagator using Cowell’s method, a step-by-step algorithm, is utilized. The simulated one-way range measurements are used for the precise orbit determination with a white noise sigma of 10 cm. We found that the observed position accuracy improvements are better than 10 m.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4764461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PAH emission features in star-forming regions and late type stars","authors":"Rahul Kumar Anand,&nbsp;Shantanu Rastogi,&nbsp;Brijesh Kumar","doi":"10.1007/s12036-023-09941-z","DOIUrl":"10.1007/s12036-023-09941-z","url":null,"abstract":"<div><p>Mid-infrared emission spectra, obtained from ISO archive, of thirteen astrophysical objects as well as computed spectra of 27 polycyclic aromatic hydrocarbon (PAH) molecules are studied. All the objects show strong aromatic infrared band (AIB) features with variations that correlate with object type. Based on AIB peak positions, the features for IRC <span>(+)</span>10216, Monoceros R2, and IC 5117 and PN-SwSt 1 are classified as type ‘A’, ‘B’ or ‘C’ for the first time. The AIBs at 6.2, 7.7 and 11.2 <span>(mu hbox {m})</span> are used to obtain band intensity ratios for 6.2/7.7 and 11.2/6.2, which respectively indicate PAH size as number of carbon atoms and the ionization conditions of the medium. The smaller value of 6.2/7.7 points towards the presence of large PAH molecules, while higher value of 11.2/6.2 ratio relates to harsh conditions around the object. In general, for star-forming regions, the 6.2/7.7 band ratio obtained is &gt;1 and the 11.2/6.2 ratio is &gt;2, while for late type carbon stars, these values are &lt;1 and &lt;2. This indicates that small/medium-sized ionized PAHs are likely in star-forming regions and large PAHs in evolved stars. For each of the 27 plain PAH molecules, the integrated intensity in these bands is obtained from the computed infrared spectra and the band ratios are calculated. The ratio 6.2/7.7 in several computed medium and large sized PAH cations is in the range of observed ratio in most objects, but some molecules show large variations in band ratios, indicating that PAHs possible in interstellar medium could be more complex and with irregular structures.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4620877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A physically-motivated perspective of Fanaroff–Riley classification of radio galaxies","authors":"Gopal-Krishna,&nbsp;Paul J. Wiita,&nbsp;Ravi Joshi,&nbsp;Dusmanta Patra","doi":"10.1007/s12036-023-09937-9","DOIUrl":"10.1007/s12036-023-09937-9","url":null,"abstract":"<div><p>A small subset of extragalactic double radio sources, termed HYbrid MOrpholgy Radio Sources (HYMORS), is distinguished by a very unusual, hybrid morphology in terms of Fanaroff–Riley (FR) classification. In HYMORS, one radio lobe appears edge-darkened (FR I), while the other shows a well-defined emission peak near its outer edge (edge-brightened, FR II). Such sources are rare, but critical for constraining the mechanism responsible for FR dichotomy, a widely debated issue in extragalactic astrophysics. Here, we highlight the need for caution in assigning FR type, in view of some upcoming observational campaigns to confirm HYMORS among the candidates. To illustrate this, we highlight the cases of three radio sources, which have been perceived to be HYMORS, including the radio galaxy 0500<span>(+)</span>630 (4C <span>(+)</span>63.07), which has been claimed to be a good, original example of a HYMORS, with a FR I western lobe and a FR II eastern lobe marked by a prominent terminal hot spot. However, its recent VLASS map at 3 GHz has revealed that the western lobe actually extends much farther out than reported and terminates in a well-defined emission peak. This implies that the source is a regular FR II radio galaxy and not a HYMORS. We also provide a brief perspective of the HYMORS phenomenon and underscore the need to confirm a FR I classification by ruling out additional FR II characteristics, such as an inward lobe-widening and spectral steepening, as well as a lack of prominent radio jet within the lobe.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4552917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}