5 citations · 20 across the 20 of their papers we have counts for
22 papers
Commissioning and on-sky performance of FiberPol: a fiber-fed spectropolarimetric system for the SAAO 1.9 m telescope
Siddharth Maharana, K. C. J. Dennison-Farrar, Sabyasachi Chattopadhyay +8
At the South African Astronomical Observatory (SAAO), we have developed FiberPol a spectropolarimetric front-end for the SpUpNIC spectrograph on the 1.9 m telescope fed by fiber…
A Slit Mask Integral Field Unit for the Robert Stobie Spectrograph on the Southern African Large Telescope: I. Instrument Development
Sabyasachi Chattopadhyay, Matthew A. Bershady, Michael P. Smith +2
Integral field spectroscopy (IFS) has been added as a new observation mode to the Robert Stobie Spectrograph (RSS), the workhorse multi-mode instrument on the Southern African Larg…
SXP 31.0 -- the 2025 near-Eddington double X-ray outburst after 26 years of quiescence
Malcolm J. Coe, Thomas M. Gaudin, Itumeleng M. Monageng +5
SXP 31.0 is an X-ray source in the Small Magellanic Cloud (SMC) that was first identified as a Be X-ray Binary (BeXRB) system when it went into X-ray outbusrst in 1998. It is now k…
Multi-wavelength observations of a jet launch in real time from the post-changing-look Active Galaxy 1ES 1927+654
Sibasish Laha, Eileen T. Meyer, Dev R. Sadaula +34
We present results from a high cadence multi-wavelength observational campaign of the enigmatic changing look AGN 1ES 1927+654 from May 2022- April 2024, coincident with an unprece…
Light scrambling and focal ratio degradation of thin multimode fibers with different core geometries
Man-Yin Leo Lee, Zhiheng Lin, Chit-Ho Hui +6
The performance of fiber-fed astronomical spectrographs is highly influenced by the properties of fibers. The near-field and far-field scrambling characteristics have a profound im…
Early Commissioning Results of Slit Mask Integral Field Units on the Southern African Large Telescope
Sabyasachi Chattopadhyaya, Matthew A. Bershady
Three fibre feed integral field units (IFUs), called Slit Mask IFUs (SMI), are being developed in the SAAO fibre-lab for the Robert Stobie Spectrograph (RSS). The smaller, 200 micr…
FiberPol-6D: Spectropolarimetric Integral Field mode for the SAAO 1.9 m Telescope using fibers
Siddharth Maharana, Sabyasachi Chattopadhyay, Matthew Bershady
Most optical spectropolarimeters built to date operate as long-slit or point-source instruments; they are inefficient for observations of extended objects such as galaxies and nebu…
SDSS-IV MaNGA: Calibration of astrophysical line-widths in the Hα region using HexPak observations
Sabyasachi Chattopadhyay, Matthew A. Bershady, David R. Law +7
We have re-observed 40 low-inclination, star-forming galaxies from the MaNGA survey ($\upsigma\sim65$~\kms) at 6.5 times higher spectral resolution ($\upsigma\sim10$…
A re-emerging bright soft-X-ray state of the changing-look Active Galactic Nucleus 1ES~1927+654: a multi-wavelength view
Ritesh Ghosh, Sibasish Laha, Eileen Meyer +24
1ES1927+654 is a nearby active galactic nucleus that has shown an enigmatic outburst in optical/UV followed by X-rays, exhibiting strange variability patterns at timescales of mont…
Slit Mask Integral Field Units for the Southern African Large Telescope
Sabyasachi Chattopadhyay, Matthew A. Bershady, Marsha J. Wolf +1
Two fibre integral field units (IFU) are being built in the SAAO fibre-lab for the Robert Stobie Spectrograph's visible arm and the future red arm. Each IFU sits in its own slit-ma…
Optimum telescope focal ratios for microlens-to-fiber coupled integral field spectrographs
Sabyasachi Chattopadhyay, Matthew A. Bershady, Marsha J. Wolf +1
We describe the optimum telescope focal ratio for a two-element, three surface, telecentric image-transfer microlens-to-fiber coupled integral field unit within the constraints imp…
The Prototype Telescope and Spectrograph System for the AMASE Project
Renbin Yan, Matthew A. Bershady, Michael P. Smith +7
We present the design of the prototype telescope and spectrograph system for the Affordable Multiple Aperture Spectroscopy Explorer (AMASE) project. AMASE is a planned project that…
Development and Characterization of a Precisely Adjustable Fiber Polishing Arm
Michael P. Smith, Sabyasachi Chattopadhyay, Andrew Hauser +3
The development of bare fiber or air-gapped microlens-fiber coupled Integral Field Units (IFUs) for astronomical applications requires careful treatment of the fiber end-faces (ter…
Optimization of telescope focal ratios for MLA-fiber coupled Integral Field Units
Sabyasachi Chattopadhyay, Matthew A. Bershady, Marsha J. Wolf +1
We have developed an analytic model for generic image transfer using microlens-coupled fibers to determine the telescope input beam speed that optimizes the lenslet clear aperture…
Fiber positioning in microlens-fiber coupled integral field unit
Sabyasachi Chattopadhyay, Matthew A. Bershady, Marsha J. Wolf +2
A generic fiber positioning strategy and a fabrication path are presented for microlens-fiber-coupled integral field units. It is assumed that microlens-produced micro-images are c…
DOTIFS: fore-optics and calibration unit design
Haeun Chung, A. N. Ramaprakash, Pravin Khodade +5
We present fore-optics and calibration unit design of Devasthal Optical Telescope Integral Field Spectrograph (DOTIFS). DOTIFS fore-optics is designed to modify the focal ratio of…
DOTIFS: spectrograph optical and opto-mechanical design
Haeun Chung, A. N. Ramaprakash, Pravin Khodade +10
Devasthal Optical Telescope Integral Field Spectrograph (DOTIFS) is a new multi-Integral Field Unit (IFU) instrument, planned to be mounted on the 3.6m Devasthal optical telescope…
DOTIFS: a new multi-IFU optical spectrograph for the 3.6-m Devasthal optical telescope
Haeun Chung, A. N. Ramaprakash, Amitesh Omar +4
Devasthal Optical Telescope Integral Field Spectrograph (DOTIFS) is a new multi-object Integral Field Spectrograph (IFS) being designed and fabricated by the Inter-University Cente…
Noise Characterization of IUCAA Digital Sampling Array Controller (IDSAC)
Sabyasachi Chattopadhyay, A. N. Ramaprakash, Bhushan Joshi +11
IUCAA Digital Sampling Array Controller (IDSAC) is a flexible and generic yet powerful CCD controller which can handle a wide range of scientific detectors. Based on an easily scal…
Multiple rooks of chess - a generic integral field unit deployment technique
Sabyasachi Chattopadhyay, A. N. Ramaprakash, Pravin Khodade +4
A new field re-configuration technique, Multiple Rooks of Chess (MRC), for multiple deployable Integral Field Spectrographs has been developed. The method involves mechanical geome…
A new photolithography based technique to mass produce microlens+fibre based integralfield units (IFUs) for 2D spectroscopy
Sabyasachi Chattopadhyay, Vishal Joshi, A. N. Ramaprakash +3
We present a novel photolithography based technique to efficiently fabricate microlens-fibre based Integral Field Units (IFUs). These IFUs are being developed for Devasthal Optical…
IDSAC - IUCAA Digital Sampler Array Controller
Sabyasachi Chattopadhyay, Pravin Chordia, A. N. Ramaprakash +3
IUCAA Digital Sampling Array Controller (IDSAC) is a generic CCD Controller which is flexible and powerful enough to control a wide variety of CCDs and CMOS detectors used for grou…