J/A+A/704/A268 FITS images of 24 bow-shock candidates (Moutzouri+, 2025)
A targeted radio survey of infrared-selected bow shock candidates.
Moutzouri M., Mackey J., Castro N., Gong Y., Jimenez-Hernandez P.,
Toala J.A., Burger-Scheidlin C., Rugel M., Carrasco-Gonzalez C., Brose R.,
Menten K.M.
<Astron. Astrophys. 704, A268 (2025)>
=2025A&A...704A.268M 2025A&A...704A.268M (SIMBAD/NED BibCode)
ADC_Keywords: Radio continuum; Nebulae; Infrared sources; Surveys
Keywords: radiation mechanisms: non-thermal - shock waves -
circumstellar matter - stars: massive - stars: winds, outflows -
radio continuum: ISM -
Abstract:
Bow shocks around massive stars have primarily been detected in IR
emission, but radio detections are becoming more frequent with the
commissioning of sensitive and large field-of-view interferometers.
Radio data probes both thermal and non-thermal emission, thereby
constraining the relativistic electron population and potentially
particle-acceleration processes. We undertook a radio survey for bow
shocks accessible from the Northern Hemisphere, based on IR catalogues
of candidates, using the Very Large Array (VLA) and the 100-m
Effelsberg Telescope, aiming for new detections and to better
characterise the multi-wavelength emission. We used Gaia DR3 to
re-calculate spatial motion of the driving stars with respect to the
surrounding stellar population. We studied the radio emission from bow
shocks using emission maps and spectral-index measurements, and
compared our results with data from catalogues and multi-wavelength
emission. Of the 24 targets observed with the VLA in the 4-12GHz
band, six were clearly detected (including two previously reported)
and 5 possibly detected. A subset of these were also observed and
detected with Effelsberg at 4-8GHz. The VLA-derived spectral index
maps indicate non-thermal emission for most sources, but the
statistical uncertainties are large for most sources and all
Effelsberg observations indicate thermal emission. Assuming thermal
emission, we obtain upper limits on the electron density within the
shocked layer. We obtained upper limits on radio emission from the bow
shock of Zeta Oph at a similar flux level to predictions from
magnetohydrodynamic simulations. Our survey marks a significant
addition to the ca. 10 previously known radio-emitting bow shocks in
the literature, and demonstrates that deep, targeted radio surveys can
have a good success rate in detecting IR-selected bow shocks.
Follow-up observations of these targets at lower and higher
frequencies are encouraged to determine whether any are non-thermal
emitters like the bow shocks of BD+433654, BD+602522, and LS2355.
Description:
FITS images for the 24 bow-shock candidates observed with the Very
Large Array (VLA) are presented, plus Effelsberg FITS images for 10 of
the sources that were also observed with the Effelsberg 100-m
telescope. All images are in units of mJy/beam. For VLA-detected bow
shocks, shown in Fig. 1 of the paper, we provide the intensity image
(labelled "i"), the spectral-index map (labelled "s") and the
spectral-index 1-sigma uncertainty map (labelled "u"). For the
marginal and undetected targets only the intensity image is provided.
With the exception of Zeta Ophiuchi, images for the 9 Effelsberg
targets are provided in 7 sub-bands centred on frequencies:
4.487 GHz - band a,
4.743 GHz - band b,
4.999 GHz - band c,
5.383 GHz - band d,
5.639 GHz - band e,
6.615 GHz - band f,
7.639 GHz - band g.
For Zeta Ophiuchi, images are provided centred on 4.951GHz and
6.599GHz. Detected sources are in the subdirectory "det", marginal
cases in subdirectory "mar" and non-detections in subdirectory "non"
Naming convention: VLA images have filename beginning with "V_" and
Effelsberg images have filename beginning with "E_". The file name
then continues with 5 characters of the target bow-shock name,
following the names in Table A.1 of the paper, skipping punctuation
marks. The final character of the name is in [a-g] for the Effelsberg
sub-bands, i for VLA intensity image, s for VLA spectral-index map and
u for its uncertainty.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 133 24 List of VLA Targets and their driving star,
sorted according to Right Ascension
list.dat 134 101 List of fits file
det/* . 60 Individual Effelsberg and VLA fits images
non/* . 15 Individual Effelsberg and VLA fits images
mar/* . 26 Individual VLA intensity maps
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See also:
J/A+A/578/A45 : E-BOSS. II. Catalogue second release (Peri+, 2015)
J/AJ/154/201 : IR properties of stellar bowshock nebulae (Kobulnicky+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- BowShock Bow shock name (1)
20- 43 A24 --- DrivingStar Driving star name (2)
45- 46 I2 h RAh Right ascension (J2000)
48- 49 I2 min RAm Right ascension (J2000)
51- 54 F4.1 s RAs Right ascension (J2000)
56 A1 --- DE- Declination sign (J2000)
57- 58 I2 deg DEd Declination (J2000)
60- 61 I2 arcmin DEm Declination (J2000)
63- 66 F4.1 arcsec DEs Declination (J2000)
68- 78 A11 --- SpType Spectral type
80- 82 A3 --- Det? [yes no?] Radio detection ?
84- 89 F6.2 km/s pmRAenv ?=- Mean proper motion along RA in the
local environment of the star
91- 96 F6.2 km/s pmDEenv ?=- Mean proper motion along DE in the
local environment of the star
98-103 F6.2 km/s pmRApec ?=- Peculiar proper motion along RA of the
star with respect to local environment
105-108 F4.2 km/s e_pmRApec ? Peculiar proper motion along RA of the
star with respect to local environment
error
110-115 F6.2 km/s pmDEpec ?=- Peculiar proper motion along DE of the
star with respect to local environment
117-120 F4.2 km/s e_pmDEpec ? Peculiar proper motion along DE of the
star with respect to local environment
error
122-126 F5.2 mas plx ?=- Parallax from Gaia DR3
128-131 F4.2 mas e_plx ? Parallax error from Gaia DR3
133 A1 --- Ref Reference (3)
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Note (1): Targets from our survey are named according to the entry
in the catalog of Kobulnicky et al. (2017AJ....154..201K 2017AJ....154..201K, Cat. J/AJ/154/201)
(GXXX.XXXX +XX.XXXX) and the E-BOSS catalog Peri et al. (2015A&A...578A..45P 2015A&A...578A..45P,
Cat. J/A+A/578/A45, table 8) (EBXX [Star ID]).
Note (2): the id of the star driving the bow shock is taken first
from bright-star catalogues, otherwise the 2MASS identifier is used
Note (3): References as follows:
1 = Kobulnicky et al. (2016ApJS..227...18K 2016ApJS..227...18K, Cat. J/ApJS/227/18)
2 = Benaglia et al. (2010A&A...517L..10B 2010A&A...517L..10B)
3 = Peri et al. (2015A&A...578A..45P 2015A&A...578A..45P, Cat. J/A+A/578/A45)
4 = Green et al. (2019A&A...625A...4G 2019A&A...625A...4G)
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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- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
21- 24 I4 --- Nx Number of pixels along X-axis
26- 29 I4 --- Ny Number of pixels along Y-axis
31- 56 A26 "datime" Obs.date Observation date
58- 66 E9.4 Hz Freq ? Frequency
70- 74 I5 Kibyte size Size of FITS file
76- 91 A16 --- FileName Name of FITS file with the subdirectory
93-134 A42 --- Title Title of the FITS file
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Acknowledgements:
Maria Moutzouri, Yan Gong, Jonathan Mackey (jmackey(at)cp.dias.ie)
(End) Jonathan Mackey [DIAS Dublin, Ireland], Patricia Vannier [CDS] 04-Nov-2025