J/ApJ/902/L1 NIR AO images of Carina's Western Wall (Hartigan+, 2020)
A JWST preview: adaptive-optics images of H2, br-γ, and K-continuum in
Carina's Western Wall.
Hartigan P., Downes T., Isella A.
<Astrophys. J., 902, L1 (2020)>
=2020ApJ...902L...1H 2020ApJ...902L...1H
ADC_Keywords: Star Forming Region; Infrared sources
Keywords: Stellar jets ; Herbig-Haro objects ; Photodissociation regions ;
Star formation ; Radiative magnetohydrodynamics ;
Astrophysical fluid dynamics
Abstract:
We present the first wide-field near-infrared adaptive-optics images
of Carina's Western Wall (G287.38-0.62), one of the brightest and most
well-defined irradiated interfaces known in a region of massive star
formation. The new narrowband H2 2.12µm, Br-γ and
K-continuum images from Gemini South trace the photoevaporative flow
from the cloud and identify locations where UV radiation from the
surrounding massive stars excites molecular hydrogen to fluoresce.
With a field of view of ∼1.5'x2.9' and spatial resolution between
60 and 110mas, the new images show a spectacular level of detail over
a large area, and presage what the James Webb Space Telescope (JWST)
should achieve. The Wall is convex in shape, with a large
triangular-shaped extension near its apex. The interface near the apex
consists of 3-4 regularly spaced ridges with projected spacings of
∼2000au, suggestive of a large-scale dynamically important magnetic
field. The northern edge of the Wall breaks into several swept-back
fragments of width ∼1800au that resemble Kelvin-Helmholtz
instabilities, and the southern part of the Wall also shows complex
morphologies including a sinusoidal-like variation with a
half-wavelength of 2500au. Though the dissociation front must increase
the density along the surface of the Wall, it does not resolve into
pillars that point back to the ionization sources, as could occur if
the front triggered new stars to form. We discovered that MHO 1630, an
H2 outflow with no clear driving source in the northern portion of
the Wall, consists of a series of bow shocks arrayed in a line.
Description:
We acquired images of Carina's Western Wall with the Adaptive Optics
Imager (GSAOI) on Gemini South between 2018 January 15 and 2018
January 19 for a program with 10 hours of queue time
(program GS-2018A-Q-123).
However, note that the Header FITS indicates 2019 January 15 as the
observation date (note added by CDS).
The images used three narrowband filters, H2 1-0 S(1) (G1121;
λ0=2.122um; Δλ=0.032um), Br-γ (G1122;
λ0=2.166um; Δλ=0.032um), and K-continuum (G1112;
λ0=2.270um; Δλ=0.034um), and employed two
pointings offset in decl. from one another by 85" to cover the region
of interest. The center of the composite image is
RAJ2000=10:43:30.6,DEJ2000=-59:35:20.
See Section 2 for further details.
Objects:
------------------------------------------------------------------------
RA (ICRS) DE Designation(s)
------------------------------------------------------------------------
10 43 34.4 -59 34 38 Carina's Western Wall = GRS G287.38 -00.62
------------------------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fits.dat 69 3 Summary of the individual FITS files used to
produce the AO image in Figure 2b
fits/* . 3 Individual FITS files
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See also:
J/MNRAS/367/513 : JHKs[3.5][4.5] photometry of NGC 3372 (Tapia+, 2006)
J/ApJS/194/5 : Carina OB stars in the CCCP catalog (Gagne+, 2011)
J/A+A/579/A130 : Near-IR BN/KL outflow images (Bally+, 2015)
J/A+A/609/A10 : NGC2264 structure and star formation history (Venuti+, 2018)
J/A+A/622/A91 : Herschel/HIFI and IRAM 30m images of OMC1 (Goicoechea+, 2019)
Byte-by-byte Description of file: fits.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)
20- 23 I4 --- Nx [1621] Number of pixels along X-axis
25- 28 I4 --- Ny [2957] Number of pixels along Y-axis
30- 39 A10 "Y/M/D" Date UT date of observation (2019-01-15)
41- 45 I5 kibyte Size [18748] Size of FITS file
47- 57 A11 --- FileName Name of the FITS file in subdirectory fits
59- 69 A11 --- Filt Band filter (see the Description section)
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History:
FITS files from electronic version of the journal
(End) Emmanuelle Perret [CDS] 22-Apr-2022