J/A+A/657/A25 A521 and Cosmic Snake ALMA and HST images (Nagy+, 2022)
Radial profiles of lensed z∼1 galaxies on sub-kiloparsec scales
Nagy D., Dessauges-Zavadsky M., Richard J., Schaerer D., Combes F.,
Messa M., Chisholm J.
<Astron. Astrophys. 657, A25 (2022)>
=2022A&A...657A..25N 2022A&A...657A..25N (SIMBAD/NED BibCode)
ADC_Keywords: Gravitational lensing ; Photometry, HST ; Radio sources
Keywords: galaxies: high-redshift - galaxies: structure -
gravitational lensing: strong - stars: formation
Abstract:
We study the spatially resolved physical properties of the Cosmic
Snake arc in MACS J1206.2-0847 and the arc in Abell 0521 (A521).
These are two strongly lensed galaxies at redshifts z=1.036 and
z=1.044. We used observations of the Hubble Space Telescope (HST) and
the Atacama Large Millimeter/submillimeter Array (ALMA). The former
gives access to the star formation rate (SFR) and stellar mass (M*),
and the latter to the H2 molecular gas mass (Mmol). HST and ALMA
observations have similar angular resolutions of 0.15"-0.2", which
with the help of strong gravitational lensing enable us to reach
spatial resolutions down to ∼30pc and ∼100pc in these two galaxies,
respectively. These resolutions are close to the resolution of
observations of nearby galaxies. We study the radial profiles of SFR,
M*, and Mmol surface densities of these high-redshift galaxies and
compare the corresponding exponential scale lengths with those of
local galaxies. We find that the scale lengths in the Cosmic Snake are
about 0.5kpc-1.5kpc, and they are 3 to 10 times larger in A521. This
is a significant difference knowing that the two galaxies have
comparable integrated properties. These high-redshift scale lengths
are nevertheless comparable to those of local galaxies, which cover a
wide distribution. The particularity of our high-redshift radial
profiles is the normalisation of the Mmol surface density profiles
(Sigma Mmol), which are offset by up to a factor of 20 with respect to
the profiles of z=0 counterparts. The SFR surface density profiles are
also offset by the same factor as {SIGMA}Mmol, as expected from the
Kennicutt-Schmidt law.
Description:
The HST images of MACS J1206.2-0847 are part of the Cluster Lensing
and Supernova survey with Hubble (CLASH)1. The Cosmic Snake was
observed in 16 HST bands (4 WFC3/UVIS, 7 ACS, and 5 WFC3/IR).We used
the 0:03" version of the maps from the CLASH archive. The exposure
time in each HST filter ranges between 2000s and 5000s.
The observations of the Cosmic Snake arc were acquired in Cycle 3
(project 2013.1.01330.S). They were performed in the extended C38-5
configuration with a maximum baseline of 1.6km and 38 antennas of the
12m array in band 6 with a total onsource integration time of 52.3min
(Dessauges-Zavadsky et al., 2019NatAs...3.1115D 2019NatAs...3.1115D). The targeted CO(4-3)
emission line was observed at 226.44GHz, corresponding to a redshift
of z=1.036. The observations of the isolated counter-image to the
north-east of the Cosmic Snake arc and A521 were obtained in Cycle 4
(project 2016.1.00643.S).
The Cosmic Snake was observed with the Plateau de Bure interferometer
(PdBI) at 113.23GHz, the redshifted frequency of the CO(2-1) line.
The observations were conducted in March 2014 using six antennas in
the extended A-configuration for an on-source integration time
of 7.6 hours.
Objects:
-------------------------------------------
RA (2000) DE Designation(s)
-------------------------------------------
12 06 12.14 -08 48 03.3 Cosmic Snake
04 54 08.6 -10 14 39 A521 = ACO 521
-------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 207 7 List of fits images
fits/* . 7 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- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 25 F6.4 arcsec/pix scale ? Scale of the image
27- 30 I4 --- Nx Number of pixels along X-axis
32- 35 I4 --- Ny Number of pixels along Y-axis
37- 62 A26 "datime" Obs.date Observation date
64- 70 F7.3 GHz Freq ? Observed frequency
72- 76 I5 Kibyte size Size of FITS file
78-114 A37 --- FileName Name of FITS file, in subdirectory fits
116-207 A92 --- Title Title of the FITS file
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Acknowledgements:
David Nagy, david.nagy(at)unige.ch
(End) Patricia Vannier [CDS] 16-Nov-2021