Observations with the 3.6-meter Devasthal optical telescope

Sagar, Ram; Kumar, Brijesh; Sharma, Saurabh

doi:10.1007/s12036-020-09652-9

Cited by 7 publications

(7 citation statements)

References 22 publications

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“…Afterglow follow-up observations using 3.6m DOT: Considering India's longitudinal advantage for the follow-up observations of GRBs, deep follow-up observations of possible afterglows of GRBs were occasionally performed (Dimple et al 2020;Kumar et al 2020;Ghosh et al 2021;Gupta et al 2021a) using India's largest 3.6-m Devasthal optical telescope located at Devasthal observatory of Aryabhatta Research Institute of Observational Sciences (ARIES) Nainital. The optical and near-infrared (NIR) backend instruments of 3.6m DOT (Pandey et al 2018;Sagar et al 2020) offer spectral and imaging capabilities from optical to NIR wavelength and are very important for deep observations of afterglows and other fast fading transients. ARIES has a long history of more than two decays for the afterglow follow-up observations.…”

Section: Introductionmentioning

confidence: 99%

Revealing nature of GRB 210205A, ZTF21aaeyldq (AT2021any) and follow-up observations with the 4K$$\times$$4K CCD imager + 3.6m DOT

et al. 2022

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Optical follow-up observations of optical afterglows of gamma-ray bursts are crucial to probe the geometry of outflows, emission mechanisms, energetics and burst environments. We performed the follow-up observations of GRB 210205A and ZTF21aaeyldq (AT2021any) using the 3.6m Devasthal optical telescope (DOT) around one day after the burst to deeper limits due to the longitudinal advantage of the place. This paper presents our analysis of the two objects using data from other collaborative facilities, i.e., 2.2m Calar Alto Astronomical Observatory (CAHA) and other archival data. Our analysis suggests that GRB 210205A is a potential dark burst once compared with the X-ray afterglow data. Also, comparing results with other known and well-studied dark GRBs samples indicate that the reason for the optical darkness of GRB 210205A could either be intrinsic faintness or a high redshift event. Based on our analysis, we also found that ZTF21aaeyldq is the third known orphan afterglow with a measured redshift except for ZTF20aajnksq (AT2020blt) and ZTF19abvizsw (AT2019pim). The multiwavelength afterglow modeling of ZTF21aaeyldq using the afterglowpy package demands a forward shock model for an ISM-like ambient medium with a rather wider jet opening angle. We determine circumburst density of n 0 ¼ 0:87 cm À3 , kinetic energy E k ¼ 3:80 Â 10 52 erg and the afterglow modeling also indicates that ZTF21aaeyldq is observed on-axis (h obs \h core ) and a gamma-ray counterpart was missed by GRBs satellites. Our results emphasize that the 3.6m DOT has a unique capability for deep follow-up observations of similar and other new transients for deeper observations as a part of time-domain astronomy in the future.Keyword. Gamma-ray burst: general-gamma-ray burst: individual: GRB 210205A and ZTF21aaeyldqmethods: data analysis-telescope.

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Section: Introductionmentioning

confidence: 99%

Revealing nature of GRB 210205A, ZTF21aaeyldq (AT2021any) and follow-up observations with the 4K$$\times$$4K CCD imager + 3.6m DOT

et al. 2022

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“…Afterglow follow-up observations using 3.6m DOT: Considering India's longitudinal advantage for the follow-up observations of GRBs, deep follow-up observations of possible afterglows of GRBs were occasionally performed (Kumar et al, 2020;Dimple et al, 2020;Ghosh et al, 2021;Gupta et al, 2021a,c) using India's largest 3.6-meter Devasthal Optical Telescope and other facilities located at Devasthal observatory of Aryabhatta Research Institute of Observational Sciences (ARIES) Nainital. The optical and near-infrared (NIR) back-end instruments of 3.6m DOT (Sagar et al, 2020;Pandey et al, 2018) offer spectral and imaging capabilities from optical to NIR wavelength and are very important for deep observations of afterglows and other fast fading transients. ARIES has a long history of more than two decays for the afterglow follow-up observations.…”

Section: Introductionmentioning

confidence: 99%

Revealing nature of GRB 210205A, ZTF21aaeyldq (AT2021any), and follow-up observations with the 4K$\times$4K CCD Imager+3.6m DOT

Gupta,

Kumar,

Pandey

et al. 2021

Preprint

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Optical follow-up observations of optical afterglows of gamma-ray bursts are crucial to probe the geometry of outflows, emission mechanisms, energetics, and burst environments. We performed the follow-up observations of GRB 210205A and ZTF21aaeyldq (AT2021any) using the 3.6m Devasthal Optical Telescope (DOT) around one day after the burst to deeper limits due to the longitudinal advantage of the place. This paper presents our analysis of the two objects using data from other collaborative facilities, i.e., 2.2m Calar Alto Astronomical Observatory (CAHA) and other archival data. Our analysis suggests that GRB 210205A is a potential dark burst once compared with the X-ray afterglow data. Also, comparing results with other known and well-studied dark GRBs samples indicate that the reason for the optical darkness of GRB 210205A could either be intrinsic faintness or a high redshift event. Based on our analysis, we also found that ZTF21aaeyldq is the third known orphan afterglow with a measured redshift except for ZTF20aajnksq (AT2020blt) and ZTF19abvizsw (AT2019pim). The multiwavelength afterglow modelling of ZTF21aaeyldq using the afterglowpy package demands a forward shock model for an ISM-like ambient medium with a rather wider jet opening angle. We determine circumburst density of n 0 = 0.87 cm −3 , kinetic energy E k = 3.80 ×10 52 erg and the afterglow modelling also indicates that ZTF21aaeyldq is observed on-axis (θ obs < θ core ) and a gamma-ray counterpart was missed by GRBs satellites. Our results emphasize that the 3.6m DOT has a unique capability for deep follow-up observations of similar and other new transients for deeper observations as a part of time-domain astronomy in the future.

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“…Recent studies by Ningombam et al (2021) and Priyatikanto et al (2023) indicate that it continues to be a globally competitive astronomical observatory and can be rated as a very good site in the Asian region. A comparison of atmospheric seeing and extinction measurements carried out ~ 2 decades ago with those estimated from recent observations taken with the 3.6-m DOT shows that sky conditions at Devasthal have not deteriorated (Sagar et al 2019(Sagar et al , 2020Joshi et al 2022). This confirms that the abundant care taken during infrastructure development and construction of the telescope buildings has paid rich dividends.…”

Section: Discussionmentioning

confidence: 55%

“…• Both optical and NIR observations taken with the 3.6-m DOT reveal that sub-arcsec quality images can be obtained for a significant fraction of photometric nights. They also indicate that performance of the telescope is at par with its peers located elsewhere in the world (Omar et al 2017;Kumar et al 2018;Sagar et al 2019Sagar et al , 2020. Consequently, the facilities at Devasthal have led a good number of national and international collaborations including the Indo-Belgian techno-scientific collaboration termed BINA (Joshi and De Cat 2019;Sagar 2023).…”

Section: Period In Yearsmentioning

confidence: 99%

Optical Telescopes at Devasthal Observatory, Nainital

Sagar

2020

Reson

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Devasthal observatory, established over a time span of ~ 5 decades, is located in central Himalayan region of Devabhumi in Nainital district of Uttarakhand state, India. Operated and maintained by the Aryabhatta Research Institute of observational sciencES (ARIES), it's location was selected after an extensive site survey. The first measurements of atmospheric seeing and extinctions at Devasthal were carried out during 1997--2001. Since 2010, three optical telescopes of 1.3-m, 3.6-m and 4-m apertures have been successfully installed at Devasthal. Optical and near-infrared observations taken with these telescopes testify to the global competitiveness of Devasthal observatory for astronomical observations. The article chronicles the collaboration with the Tata Institute of Fundamental Research, beginning around 1996, for the purpose of establishing the observatory. A brief overview of the main science results obtained so far, using these facilities, is also presented.

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Observations with the 3.6-meter Devasthal optical telescope

Cited by 7 publications

References 22 publications

Revealing nature of GRB 210205A, ZTF21aaeyldq (AT2021any) and follow-up observations with the 4K$$\times$$4K CCD imager + 3.6m DOT

Revealing nature of GRB 210205A, ZTF21aaeyldq (AT2021any) and follow-up observations with the 4K$$\times$$4K CCD imager + 3.6m DOT

Revealing nature of GRB 210205A, ZTF21aaeyldq (AT2021any), and follow-up observations with the 4K$\times$4K CCD Imager+3.6m DOT

Optical Telescopes at Devasthal Observatory, Nainital

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