An automated pipeline for Ultra-Violet Imaging Telescope

Ghosh, S. K.; Tandon, S. N.; K., Singh, Sultan; Shelat, D. S.; TAHLANI, P.; Singh, Amit Kumar; Srinivasan, T. P.; Joseph, P.; Devaraj, A.; George, Koshy; Mohan, Rekhesh; Postma, J.; Stalin, C. S.

doi:10.1007/s12036-022-09842-7

Cited by 5 publications

(2 citation statements)

References 3 publications

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“…The observed images of SMC were reduced using the UVIT L2 pipeline version 6.3 (Ghosh et al 2021(Ghosh et al , 2022. This pipeline corrects the observations for geometric distortion, flat field as well as spacecraft drift.…”

Section: Observations and Reductionsmentioning

confidence: 99%

UVIT Observations of the Small Magellanic Cloud: Point-source Catalog

Devaraj

Joseph

Stalin

et al. 2023

ApJ

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Three fields in the outskirts of the Small Magellanic Cloud were observed by the UltraViolet Imaging Telescope (UVIT) on board AstroSat, between 2017 December 31 and 2018 January 1. The observations were carried out on a total of seven filters, three in the far-ultraviolet (FUV; 1300–1800 Å) band and four in the near-ultraviolet (NUV; 2000–3000 Å) band. We carried out photometry of these observations that have a spatial resolution better than 1.″5. We present here the first results of this work, which is a matched catalog of 11,241 sources detected in three FUV and four NUV wavelengths. We make the catalog available online, which would be of use to the astronomical community to address a wide variety of astrophysical problems. We provide an expression to estimate the total count rate in the full point-spread function of UVIT that also incorporates the effect of saturation.

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Section: Observations and Reductionsmentioning

confidence: 99%

UVIT Observations of the Small Magellanic Cloud: Point-source Catalog

Devaraj

Joseph

Stalin

et al. 2023

ApJ

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“…NGC 4395 was observed by UVIT on 2018 February 27 in the photon counting mode with the default frame rate of ∼34 frames per second. We directly downloaded the level 2 (L2) science-ready images processed using the official L2 pipeline (Ghosh et al 2022) of the UVIT-Payload Operations Centre at the Indian Institute of Astrophysics, Bangalore and transferred to the Indian Space Science Data Center (ISSDC) for archival and dissemination. In the combined images from ISSDC, we found the exposure time to be lesser than the sum of the individual exposures (orbit-wise images).…”

Section: Uvmentioning

confidence: 99%

Star Formation in the Dwarf Seyfert Galaxy NGC 4395: Evidence for Both AGN and SN Feedback?

Payel

Stalin

Saikia

et al. 2023

ApJ

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We present a detailed multiwavelength study of star formation in the dwarf galaxy NGC 4395, which hosts an active galactic nucleus (AGN). From our observations with the Ultra-Violet Imaging Telescope, we have compiled a catalog of 284 star-forming (SF) regions, out of which we could detect 120 SF regions in Hα observations. Across the entire galaxy, we found the extinction-corrected star formation rate (SFR) in the far ultraviolet (UV) to range from 2.0 × 10−5 M ⊙ yr−1 to 1.5 × 10−2 M ⊙ yr−1 with a median of 3.0 × 10−4 M ⊙ yr−1, and the age to lie in the range of ∼1 to 98 Myr with a median of 14 Myr. In Hα we found the SFR to range from 7.2 × 10−6 M ⊙ yr−1 to 2.7 × 10−2 M ⊙ yr−1 with a median of 1.7 × 10−4 M ⊙ yr−1, and the age to lie between 3 to 6 Myr with a median of 5 Myr. The stellar ages derived from Hα show a gradual decline with galactocentric distance. We found three SF regions close to the center of NGC 4395 with high SFRs both from Hα and UV, which could be attributed to feedback effects from the AGN. We also found six other SF regions in one of the spiral arms having higher SFRs. These are very close to supernova remnants, which could have enhanced the SFR locally. We obtained a specific SFR (SFR per unit mass) for the whole galaxy of 4.64 × 10−10 yr−1.

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Star formation history of the post-collisional Cartwheel galaxy using AstroSat/UVIT FUV images

Mayya,

Barway,

Gómez-González

et al. 2023

Monthly Notices of the Royal Astronomical Society

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We present the results obtained by analysing the new AstroSat Ultra-Violet Imaging Telescope (UVIT) far-ultraviolet (FUV) image of the collisional-ring galaxy Cartwheel. The FUV emission is principally associated with the star-forming outer ring, with no ultraviolet detection from the nucleus and inner ring. A few sources are detected in the region between the inner and the outer rings, all of which lie along the spokes. The FUV fluxes from the detected sources are combined with aperture-matched multiband photometric data from archival images to explore the post-collision star formation history of the Cartwheel. The data were corrected for extinction using AV derived from the Balmer decrement ratios and commonly used extinction curves. We find that the ring regions contain stellar populations of a wide range of ages, with the bulk of the FUV emission coming from non-ionizing stars, formed over the last 20–150 Myr, that are ∼25 times more massive than the ionizing populations. On the other hand, regions belonging to the spokes have negligible current star formation, with the age of the dominant older population systematically increasing as its distance from the outer ring increases. The presence of populations of a wide range of ages in the ring suggests that the stars formed in the wave in the past were dragged along it to the current position of the ring. We derive an average steady star formation rate, SFR = 5 ${\rm M}_{\odot }\, {\rm yr}^{-1}$, over the past 150 Myr, with an increase to ∼18 ${\rm M}_{\odot }\, {\rm yr}^{-1}$ in the recent 10 Myr.

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An automated pipeline for Ultra-Violet Imaging Telescope

Cited by 5 publications

References 3 publications

UVIT Observations of the Small Magellanic Cloud: Point-source Catalog

UVIT Observations of the Small Magellanic Cloud: Point-source Catalog

Star Formation in the Dwarf Seyfert Galaxy NGC 4395: Evidence for Both AGN and SN Feedback?

Star formation history of the post-collisional Cartwheel galaxy using AstroSat/UVIT FUV images

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