J/A+A/687/A31 LOFAR HBA 144MHz images of 5 galaxy clusters (Timmerman+, 2024)
The first high-redshift cavity power measurements of cool-core galaxy clusters
with the International LOFAR Telescope.
Timmerman R., van Weeren R.J., Botteon A., Roettgering H.J.A.,
Morabito L.K., Sweijen F.
<Astron. Astrophys. 687, A31 (2024)>
=2024A&A...687A..31T 2024A&A...687A..31T (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Galaxies, radio ; Radio continuum
Keywords: methods: observational - galaxies: active -
galaxies: clusters: general - large-scale structure of Universe -
radio continuum: galaxies - X-rays: galaxies: clusters
Abstract:
Radio-mode feedback associated with the active galactic nuclei (AGN)
at the cores of galaxy clusters injects large amount of energy into
the intracluster medium (ICM), offsetting radiative losses through
X-ray emission. This mechanism prevents the ICM from rapidly cooling
down and fueling extreme starburst activity as it accretes onto the
central galaxies, and is therefore a key ingredient in the evolution
of galaxy clusters. However, the influence and mode of feedback at
high redshifts (z∼1) remains largely unknown. Low-frequency
sub-arcsecond resolution radio observations taken with the
International LOFAR Telescope have demonstrated their ability to
assist X-ray observations with constraining the energy output from the
AGNs (or "cavity power") in galaxy clusters, thereby enabling research
at higher redshifts than before. In this pilot project, we test this
hybrid method on a high redshift (0.6<z<1.3) sample of 13 galaxy
clusters for the first time with the aim of verifying the performance
of this method at these redshifts and providing the first estimates of
the cavity power associated with the central AGN for a sample of
distant clusters. We were able to detect clear radio lobes in three
out of thirteen galaxy clusters at redshifts 0.7<z<0.9, and use these
detections in combination with ICM pressures surrounding the radio
lobes obtained from standard profiles to calculate the corresponding
cavity powers of the AGNs. By combining our results with the
literature, the current data appear to suggest that the average cavity
power peaked at a redshift of z∼0.4 and slowly decreases toward higher
redshifts. However, we require more and tighter constraints on the
cavity volume and a better understanding of our observational
systematics to confirm any deviation of the cavity power trend from a
constant level.
Description:
Reduced LOFAR HBA (144MHz) images of EGSXG J1420.5+5308,
RX J1716+6708, 4C 67.26, EGSXG J1416.2+5205, RX J1226+3333 and
CL J1415+3612. Note that there are large uncertainties on the
flux scale of these images.
Objects:
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RA (2000) DE Designation(s)
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14 20 32.6 +53 08 21 EGSXG J1420.5+5308 = CXOU J142033.6+530825
17 16 49.2 +67 08 23 RX J1716+6708 = ClG J1716+6708
17 16 36.7 +67 08 31 4C 67.26 = LEDA 2821727
14 16 17.0 +52 05 57 EGSXG J1614.2+5205 = CXOEGS J141616.9+520556
12 26 58.1 +33 32 49 RX J1226+3333 = ClG J1226+3332
14 15 11.1 +36 12 03 CL J1415+3612 = ClG J1415+3611
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 134 5 List of fits images
fits/* . 5 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- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny Number of pixels along Y-axis
30- 48 A19 "datime" Obs.date Observation date
50- 54 F5.3 MHz Freq Observed frequency
56- 60 I5 Kibyte size Size of FITS file
62- 83 A22 --- FileName Name of FITS file, in subdirectory fits
85-134 A50 --- Title Title of the FITS file
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Acknowledgements:
Roland Timmerman, rtimmerman(at)strw.leidenuniv.nl
(End) R. Timmerman [Leiden, The Netherlands], P. Vannier [CDS] 11-Apr-2024