JUDE: An Ultraviolet Imaging Telescope pipeline

Murthy, Jayant; Rahna, P. T.; Sutaria, Firoza; Safonova, Margarita; Gudennavar, S. B.; Bubbly, S. G.

doi:10.1016/j.ascom.2017.07.001

Cited by 16 publications

(19 citation statements)

References 13 publications

(18 reference statements)

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“…Our results serve as a validation of both the UVIT processing software and our alternative set of tools (Murthy et al 2016). UVIT is beginning to reach its potential and with the opening of the satellite to guest observers, including the international community, we may expect a flood of results in the near future.…”

Section: Discussionmentioning

confidence: 83%

Investigating the in-flight performance of the UVIT payload on AstroSat

Rahna

Murthy

Safonova³

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We have studied the performance of the Ultraviolet Imaging Telescope payload on AstroSat and derived a calibration of the FUV and NUV instruments on board. We find that the sensitivity of both the FUV and NUV channels is as expected from ground calibrations, with the FUV effective area about 35% and the NUV effective area about the same as that of GALEX. The point spread function of the instrument is on the order of 1.2 -1.6 . We have found that pixel-to-pixel variations in the sensitivity are less than 10% with spacecraft motion compensating for most of the flat-field variations. We derived a distortion correction but recommend that it be applied post-processing as part of an astrometric solution.

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Section: Discussionmentioning

confidence: 83%

Investigating the in-flight performance of the UVIT payload on AstroSat

Rahna

Murthy

Safonova³

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…The satellite is affected by a rather unstable pointing, which makes the target wobble around the centre of the detector with an amplitude of several tens of pixels. The data reduction pipeline we employed, thoroughly described in Murthy et al (2017) and Rahna et al (2017), corrects for this pointing jitter. We further employed the BLISS-mapping tool as described in Cubillos et al (2013) to check for the presence of residual pixel-to-pixel sensitivity variations without finding any.…”

Section: Ultraviolet and Optical Photometrymentioning

confidence: 99%

Characterization of the HD 219134 multiplanet system I. Observations of stellar magnetism, wind, and high-energy flux★

Folsom

Fossati

Wood

et al. 2018

Monthly Notices of the Royal Astronomical Society

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HD 219134 hosts several planets, with seven candidates reported, and the two shortest period planets are rocky (4-5 M ⊕ ) and transit the star. Here we present contemporaneous multiwavelength observations of the star HD 219134. We observed HD 219134 with the Narval spectropolarimeter at the Observatoire du Pic du Midi, and used Zeeman Doppler Imaging to characterise its large-scale stellar magnetic field. We found a weak poloidal magnetic field with an average unsigned strength of 2.5 G. From these data we confidently confirm the rotation period of 42 days, measure a stellar inclination of 77±8 • , and find evidence for differential rotation. The projected obliquity of the two transiting super-Earths is therefore between 0 and 20 • . We employed HST STIS observations of the Lyα line to derive a stellar wind mass-loss rate of half the solar value (10 −14 M ⊙ yr −1 ). We further collected photometric transit observations of the closest planet at near-UV wavelengths centred on the Mgii h&k lines with As-troSat. We found no detectable absorption, setting an upper limit on the transit depth of about 3%, which rules out the presence of a giant magnesium cloud larger than 9R planet . Finally, we estimated the high-energy flux distribution of HD 219134 as seen by planets b and c. These results present a detailed contemporaneous characterisation of HD 219134, and provide the ingredients necessary for accurately modelling the high-energy stellar flux, the stellar wind, and their impact on the two shortest-period planets, which will be presented in the second paper of this series.

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“…In its standard operating mode, UVIT will take images of the sky with a frame rate of 29 s −1 , which are stored on board and then sent to the Indian Space Science Data Centre (ISSDC), where the data are written into instrument-specific Level 1 data files. Murthy et al (2017) have written a set of procedures (JUDE) to read the Level 1 data, extract the photon events from each frame, correct for spacecraft motion (image registration), and add into an image. We used astrometry.net (Lang et al 2010) for an astrometric calibration and Rahna et al (2017) and Tandon et al (2017a), for a photometric calibration.…”

Section: Observationsmentioning

confidence: 99%

Planetary nebulae with UVIT

Rao

Marco

Krishna

et al. 2018

A&A

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The high excitation planetary nebula, NGC 6302, has been imaged in two far-ultraviolet (FUV) filters, F169M (Sapphire; λeff: 1608 Å) and F172M (Silica; λeff: 1717 Å) and two near-UV (NUV) filters, N219M (B15; λeff: 2196 Å) and N279N (N2; λeff: 2792 Å) with the Ultra Violet Imaging Telescope (UVIT). The FUV F169M image shows faint emission lobes that extend to about 5 arcmin on either side of the central source. Faint orthogonal collimated jet-like structures are present on either side of the FUV lobes through the central source. These structures are not present in the two NUV filters or in the FUV F172M filter. Optical and infrared (IR) images of NGC 6302 show bright emission bipolar lobes in the east-west direction with a massive torus of molecular gas and dust seen as a dark lane in the north-south direction. The FUV lobes are much more extended and oriented at a position angle of 113°. They and the jet-like structures might be remnants of an earlier evolutionary phase, prior to the dramatic explosive event that triggered the Hubble type bipolar flows approximately 2200 years ago. The source of the FUV lobe and jet emission is not known, but is likely due to fluorescent emission from H2 molecules. The cause of the difference in orientation of optical and FUV lobes is not clear and, we speculate, could be related to two binary interactions.

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JUDE: An Ultraviolet Imaging Telescope pipeline

Cited by 16 publications

References 13 publications

Investigating the in-flight performance of the UVIT payload on AstroSat

Investigating the in-flight performance of the UVIT payload on AstroSat

Characterization of the HD 219134 multiplanet system I. Observations of stellar magnetism, wind, and high-energy flux★

Planetary nebulae with UVIT

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