J/A+A/684/A73 Polarimetric Differential Imaging with VLT/NACO (de Regt+, 2024)
Polarimetric differential imaging with VLT/NACO.
A comprehensive PDI pipeline for NACO data (PIPPIN).
de Regt S., Ginski C., Kenworthy M.A., Caceres C., Garufi A.,
Gledhill T.M., Hales A.S., Huelamo N., Kospal A., Millar-Blanchaer M.A.,
Perez S., Schreiber M.R.
<Astron. Astrophys. 684, A73 (2024)>
=2024A&A...684A..73D 2024A&A...684A..73D (SIMBAD/NED BibCode)
ADC_Keywords: YSOs ; Polarization ; Infrared
Keywords: methods: observational - techniques: polarimetric -
planets and satellites: formation - protoplanetary disks
Abstract:
The observed diversity of exoplanets can possibly be traced back to
the planet formation processes. Planet-disk interactions induce
sub-structures in the circumstellar disk that can be revealed via
scattered light observations. However, a high-contrast imaging
technique such as polarimetric differential imaging (PDI) must first
be applied to suppress the stellar diffraction halo.
In this work we present the PDI PiPelIne for NACO data (PIPPIN), which
reduces the archival polarimetric observations made with the NACO
instrument at the Very Large Telescope. Prior to this work, such a
comprehensive pipeline to reduce polarimetric NACO data did not exist.
We identify a total of 243 datasets of 57 potentially young stellar
objects observed before NACO's decommissioning.
The PIPPIN pipeline applies various levels of instrumental
polarisation correction and is capable of reducing multiple observing
setups, including half-wave plate or de-rotator usage and wire-grid
observations. A novel template-matching method is applied to assess
the detection significance of polarised signals in the reduced data.
In 22 of the 57 observed targets, we detect polarised light resulting
from a scattering of circumstellar dust. The detections exhibit a
collection of known sub-structures, including rings, gaps, spirals,
shadows, and in- or outflows of material. Since NACO was equipped with
a near-infrared wavefront sensor, it made unique polarimetric
observations of a number of embedded protostars. This is the first
time detections of the Class I objects Elia 2-21 and YLW 16A have been
published. Alongside the outlined PIPPIN pipeline, we publish an
archive of the reduced data products, thereby improving the
accessibility of these data for future studies.
Description:
This dataset consists of the reduced data products generated with
PIPPIN (PDI pipeline for NACO data). PIPPIN employs the Polarimetric
Differential Imaging (PDI) technique to distinguish the polarised
scattered light from the (largely) un-polarised stellar light. As a
result, circumstellar dust can be uncovered around young stellar
objects. PIPPIN was specifically developed to reduce the archival
polarimetric observations made by the VLT/NACO instrument. During its
operation, NACO employed different instrument configurations (e.g.
half-wave plate or de-rotator usage, Wollaston beam-splitter or
wiregrid observations) which are appropriately handled by PIPPIN. As
part of the PDI reduction, PIPPIN performs various levels of
corrections for instrumental polarisation and crosstalk.
See https://pippin-naco.readthedocs.io/ for more information on
PIPPIN.
VLT/NACO polarimetric observations of 57 (potential) young stellar
object, reduced with the PIPPIN pipeline. The data were taken between
2003-2019 using various instrument setups.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
sources.dat 60 57 List of studied sources
data/* . 57 Individual sets of data files
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Byte-by-byte Description of file: sources.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- Name Star name
25- 26 I2 h RAh Right ascension (J2000)
28- 29 I2 min RAm Right ascension (J2000)
31- 35 F5.2 s RAs Right ascension (J2000)
37 A1 --- DE- Declination sign (J2000)
38- 39 I2 deg DEd Declination (J2000)
41- 42 I2 arcmin DEm Declination (J2000)
44- 47 F4.1 arcsec DEs Declination (J2000)
49- 60 A12 --- FileName Name of the set of data file in
subdirectory data
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Acknowledgements:
Sam de Regt, regt(at)strw.leidenuniv.nl
(End) Sam de Regt [Leiden Observatory], Patricia Vannier [CDS] 04-Mar-2024