The LOFAR Two-meter Sky Survey: Deep Fields Data Release 1

Tasse, C.; Shimwell, T. W.; Hardcastle, M. J.; O’Sullivan, Shane; Weeren, R. J. van; Best, P. N.; Bester, L.; Hugo, B.; Smirnov, O.; Sabater, J.; Calistro-Rivera, G.; Gasperin, F. de; Morabito, L. K.; Röttgering, H. J. A.; Williams, W. L.; Bonato, M.; Bondì, M.; Botteon, A.; Brüggen, M.; Brunetti, G.; Chyży, K. T.; Garrett, M. A.; Gürkan, G.; Jarvis, M. J.; Kondapally, R.; Mandal, S.; Prandoni, I.; Repetti, Audrey; Retana-Montenegro, E.; Schwarz, Dominik J.; Shulevski, A.; Wiaux, Yves

doi:10.1051/0004-6361/202038804

Cited by 164 publications

(85 citation statements)

References 78 publications

(73 reference statements)

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“…The data-reduction procedure includes the correction for the direction-independent and direction-dependent effects that are caused by the instrument and the ionosphere. We make use of the latest version of the pipelines PREFACTOR 4 (van Weeren et al 2016a; Williams et al 2016;de Gasperin et al 2019) and ddf-pipeline 5 (Tasse 2014a,b;Smirnov & Tasse 2015;Tasse et al 2018Tasse et al , 2021 for the directionindependent and direction-dependent calibration, respectively. The flux scale of the LOFAR data is calibrated according to the Scaife & Heald (2012) scale using the 3C 196 model that has a total flux density of 83.1 Jy at 150 MHz.…”

Section: Lofarmentioning

confidence: 99%

Discovery of a supercluster in the eROSITA Final Equatorial Depth Survey: X-ray properties, radio halo, and double relics

Ghirardini

Bulbul

Hoang

et al. 2021

A&A

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Aims. We examine the X-ray, optical, and radio properties of the member clusters of a new supercluster discovered during the SRG/eROSITA Performance Verification phase. Methods. We analyzed the 140 deg2 eROSITA Final Equatorial Depth Survey (eFEDS) field observed during the Performance Verification phase to a nominal depth of about 2.3 ks. In this field, we detect a previously unknown supercluster consisting of a chain of eight galaxy clusters at z ~ 0.36. The redshifts of these members were determined through Hyper Suprime-Cam photometric measurements. We examined the X-ray morphological and dynamical properties, gas, and total mass out to R500 of the members and compare these with the same properties of the general population of clusters detected in the eFEDS field. We further investigated the gas in the bridge region between the cluster members for a potential WHIM detection. We also used radio follow-up observations with LOFAR and uGMRT to search for diffuse emission and constrain the dynamic state of the system. Results. We do not find significant differences between the morphological parameters and properties of the intra-cluster medium of the clusters embedded in this large-scale filament and those of the eFEDS clusters. We also provide upper limits on the electron number density and mass of the warm-hot intergalactic medium as provided by the eROSITA data. These limits are consistent with previously reported values for the detections in the vicinity of clusters of galaxies. In LOFAR and uGMRT follow-up observations of the northern part of this supercluster, we find two new radio relics and a radio halo that are the result of major merger activity in the system. Conclusions. These early results show the potential of eROSITA to probe large-scale structures such as superclusters and the properties of their members. Our forecasts show that we will be able to detect about 450 superclusters, with approximately 3000 member clusters located in the eROSITA_DE region at the final eROSITA all-sky survey depth, enabling statistical studies of the properties of superclusters and their constituents embedded in the cosmic web.

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Section: Lofarmentioning

confidence: 99%

Discovery of a supercluster in the eROSITA Final Equatorial Depth Survey: X-ray properties, radio halo, and double relics

Ghirardini

Bulbul

Hoang

et al. 2021

A&A

Self Cite

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“…To improve quality and sample size in studying the radio spectral properties at both low and high frequency, observations with similar spatial resolutions and high sensitivity at multiple frequencies are essential. The recently released high-sensitivity lowfrequency (< 150 MHz) data from the Low Frequency Array (LO-FAR) large surveys (e.g., de Gasperin et al 2021;Tasse et al 2021;Sabater et al 2021) and the undergoing joint project, SuperMIGH-TEE, which combines the MeerKAT and uGMRT telescopes to observe the MIGHTEE survey regions at 0.5-2.7 GHz with the same angular resolution (∼ 5 ′′ ) and similar sensitivity, will dramatically advance the studies of the radio spectrum.…”

Section: Limitationsmentioning

confidence: 99%

Radio spectral properties of star-forming galaxies in the MIGHTEE-COSMOS field and their impact on the far-infrared-radio correlation

Vaccari

Smail

et al. 2021

Monthly Notices of the Royal Astronomical Society

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We study the radio spectral properties of 2,094 star-forming galaxies (SFGs) by combining our early science data from the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) survey with VLA, GMRT radio data, and rich ancillary data in the COSMOS field. These SFGs are selected at VLA 3 GHz, and their flux densities from MeerKAT 1.3 GHz and GMRT 325 MHz imaging data are extracted using the ‘super-deblending’ technique. The median radio spectral index is $\alpha _{\rm 1.3\, GHz}^{\rm 3\, GHz}=-0.80\pm 0.01$ without significant variation across the rest-frame frequencies ∼1.3–10 GHz, indicating radio spectra dominated by synchrotron radiation. On average, the radio spectrum at observer-frame 1.3–3 GHz slightly steepens with increasing stellar mass with a linear fitted slope of β = −0.08 ± 0.01, which could be explained by age-related synchrotron losses. Due to the sensitivity of GMRT 325 MHz data, we apply a further flux density cut at 3 GHz (S3 GHz ≥ 50 μJy) and obtain a sample of 166 SFGs with measured flux densities at 325 MHz, 1.3 GHz, and 3 GHz. On average, the radio spectrum of SFGs flattens at low frequency with the median spectral indices of $\alpha ^{\rm 1.3\, GHz}_{\rm 325\, MHz}=-0.59^{+0.02}_{-0.03}$ and $\alpha ^{\rm 3.0\, GHz}_{\rm 1.3\, GHz}=-0.74^{+0.01}_{-0.02}$. At low frequency, our stacking analyses show that the radio spectrum also slightly steepens with increasing stellar mass. By comparing the far-infrared-radio correlations of SFGs based on different radio spectral indices, we find that adopting $\alpha _{\rm 1.3\, GHz}^{\rm 3\, GHz}$ for k-corrections will significantly underestimate the infrared-to-radio luminosity ratio (qIR) for >17 per cent of the SFGs with measured flux density at the three radio frequencies in our sample, because their radio spectra are significantly flatter at low frequency (0.33–1.3 GHz).

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“…The third source, ILT J125453.46+542923.4, was initially included because its elongated morphology in the LoTSS DR1 images suggested that this was a genuine GSJ. However, subsequent improvements to the LoTSS image processing pipeline, included in the DR2 release (Tasse et al 2021), no longer showed the elongated radio emission so that we no longer consider this source to be a genuine GSJ. The VLA data (see Figure 2) confirmed that this is not a genuine GSJ.…”

Section: Sample Selectionmentioning

confidence: 99%

Investigating the spectra and physical nature of galaxy scale jets

Webster

Croston

Harwood

et al. 2021

Monthly Notices of the Royal Astronomical Society

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Previous studies have shown that physically small, low-luminosity radio galaxies, which we refer to as galaxy scale jets (GSJ), could potentially have a significant effect upon the host galaxy’s evolution. Using 6″ resolution images taken from the first release of the LOFAR Two Metre Sky Survey (LoTSS DR1), we identified a representative sample of nine potential GSJ for which we obtained high-resolution, 2-4 GHz data using the Karl G. Jansky Very Large Array (VLA). Using these data we aim to verify the GSJ nature of these sources as well as investigating the potential role of feedback. Our VLA images reveal a diversity of structures, confirm the hosts for four of the sources and find that a fifth is the first known example of a galaxy-scale remnant showing that some radio galaxies never grow beyond the GSJ stage. We also derive spectral ages and the first estimates of the lobe expansion speeds of GSJ. We find our GSJ have maximum spectral ages of 60 Myr with most between about 5 and 20 Myr, consistent with being located along an evolutionary path joining compact sources and larger radio galaxies. We find lobe advance speeds a few times the local sound speed, with most GSJ predicted to be driving strong shocks into their environment and having a significant impact upon the host’s evolution. Our discovery of a remnant GSJ, which will eventually transfer all of its energy directly into the local environment, represents an important and previously hidden aspect of AGN life cycles.

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The LOFAR Two-meter Sky Survey: Deep Fields Data Release 1

Cited by 164 publications

References 78 publications

Discovery of a supercluster in the eROSITA Final Equatorial Depth Survey: X-ray properties, radio halo, and double relics

Discovery of a supercluster in the eROSITA Final Equatorial Depth Survey: X-ray properties, radio halo, and double relics

Radio spectral properties of star-forming galaxies in the MIGHTEE-COSMOS field and their impact on the far-infrared-radio correlation

Investigating the spectra and physical nature of galaxy scale jets

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