J/A+A/689/A70 [FeII] 1.644um imaging survey of 5 PNe (Akras+, 2024)
[Fe II] 1.644um imaging survey of planetary nebulae with low-ionisation
structures.
Akras S., Aleman I., Goncalves R.D., Ramos-Larios G., Bouvis K.
<Astron. Astrophys. 689, A70 (2024)>
=2024A&A...689A..70A 2024A&A...689A..70A (SIMBAD/NED BibCode)
ADC_Keywords: Planetary nebulae; Interstellar medium ; Infrared
Keywords: shock waves - ISM: atoms - ISM: jets and outflows -
photon-dominated region (PDR) - infrared: general
Abstract:
Low-ionisation structures (LISs) are commonly found in planetary
nebulae (PNe), but they are still poorly understood. The recent
discovery of unforeseen molecular hydrogen gas (H2) has impacted
what we think we know about these microstructures and PNe. To obtain
an overall understanding of LISs, we carried out an [FeII] 1.644um
imagery survey in PNe with LISs, with the aim to detect the [FeII]
1.644um emission line, a common tracer of shocks. We present the first
detection of [FeII] 1.644um line directly associated with the LISs
in four out of five PNe. The theoretical H I 12-4 recombination line
was also computed either from the Brgamma or the Hbeta line and
subtracted from the observed narrow-band line fluxes. The [FeII]
1.644um flux ranges from 1 to 40x10-15erg/cm2/s and the
intensity from 2 to 90x10-5erg/s/cm2/sr. The
R(Fe)=[FeII]1.644mu/Brgamma line ratio was also computed and found to
range between 0.5 and 7. In particular, the [FeII] 1.644um line was
detected in NGC 6543 (R(Fe)<0.15), along with the outer pairs of LISs
in NGC 7009 (R(Fe)<0.25) and the jet-like LISs in IC 4634 (R(Fe)∼1)
and in several LISs in NGC 6571 (2<R(Fe)<7). The low R(Fe) result for
NGC 6543 is attributed to the UV radiation from the central star. In
contrast, the higher values in NGC 6571 and IC 4634 are indicative of
shocks. The moderate R(Fe) in NGC 7009 likely indicates the
contribution of both mechanisms.
Description:
A near-IR (NIR) narrow-band imaging survey of PNe with LISs was
carried out in 2017 (February 20, March 25, June 6 and 9, and July 2
and 3, Program ID: GN-2017A-Q-58, PI: S. Akras) in service mode,
using the Near InfraRed Imager and Spectrometer on the Gemini-North
Telescope at Mauna Kea in Hawaii.
The narrow-band filter G0215 was used to isolate the [FeII] line
centered at 1.644um, while the narrow-band H-continuum filter (G0214)
at 1.570um was used to determine and finally remove any adjacent
continuum emission.
Narrow-band G0215 ([FeII]+HI 12-4) emission line and
continuum-subtracted [FeII]+HI 12-4 emission line images of NGC6210,
IC4634, NGC6543, NGC6751 and NGC7009
Objects:
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RA (2000) DE Designation(s)
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21 04 10.82 -11 21 48.6 NGC 7009 = PN G037.7-34.5
17 58 33.40 +66 37 58.7 NGC 6543 = PN G096.4+29.9
19 05 55.53 -05 59 32.3 NGC 6751 = PN G029.2-05.9
16 44 29.52 +23 47 59.4 NGC 6210 = PN G043.1+37.7
17 01 33.58 -21 49 33.0 IC 4634 = PN G000.3+12.2
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 128 12 List of fits images
fits/* . 12 Individual fits images
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name PN name
9- 10 I2 h RAh Right Ascension (J2000)
12- 13 I2 min RAm Right Ascension (J2000)
15- 19 F5.2 s RAs Right Ascension (J2000)
20 A1 --- DE- Declination sign (J2000)
21- 22 I2 deg DEd Declination (J2000)
24- 25 I2 arcmin DEm Declination (J2000)
27- 30 F4.1 arcsec DEs Declination (J2000)
32- 36 F5.3 arcsec/pix scale Scale of the image
38- 41 I4 --- Nx Number of pixels along X-axis
43- 46 I4 --- Ny Number of pixels along Y-axis
48- 51 I4 Kibyte size Size of FITS file
53- 64 A12 --- FileName Name of FITS file, in subdirectory fits
66-128 A63 --- Title Title of the FITS file
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Acknowledgements:
Stavros Akras, stavrosakras(at)gmail.com
(End) Patricia Vannier [CDS] 29-Jul-2024