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42 results on '"Weeren, R.J. van"'

1. V-LoTSS: The circularly polarised LOFAR Two-metre Sky Survey★

Author

Callingham, J.R., Shimwell, T.W., Vedantham, H.K., Bassa, C.G., O’Sullivan, S.P., Yiu, T.W.H., Bloot, S., Best, P.N., Hardcastle, M.J., Haverkorn, M., Kavanagh, R.D., Lamy, L., Pope, B.J.S., Röttgering, H.J.A., Schwarz, D.J., Tasse, C., Weeren, R.J. van, White, G.J., Zarka, P., Bomans, D.J., Bonafede, A., Bonato, M., Botteon, A., Bruggen, M., Chyży, K.T., Drabent, A., Emig, K.L., Gloudemans, A.J., Gürkan, G., Hajduk, M., Hoang, D.N., Hoeft, M., Iacobelli, M., Kadler, M., Kunert-Bajraszewska, M., Mingo, B., Morabito, L.K., Nair, D.G., Pérez-Torres, M., Ray, T.P., Riseley, C.J., Rowlinson, A., Shulevski, A., Sweijen, F., Timmerman, R., Vaccari, M., Zheng, J., Callingham, J.R., Shimwell, T.W., Vedantham, H.K., Bassa, C.G., O’Sullivan, S.P., Yiu, T.W.H., Bloot, S., Best, P.N., Hardcastle, M.J., Haverkorn, M., Kavanagh, R.D., Lamy, L., Pope, B.J.S., Röttgering, H.J.A., Schwarz, D.J., Tasse, C., Weeren, R.J. van, White, G.J., Zarka, P., Bomans, D.J., Bonafede, A., Bonato, M., Botteon, A., Bruggen, M., Chyży, K.T., Drabent, A., Emig, K.L., Gloudemans, A.J., Gürkan, G., Hajduk, M., Hoang, D.N., Hoeft, M., Iacobelli, M., Kadler, M., Kunert-Bajraszewska, M., Mingo, B., Morabito, L.K., Nair, D.G., Pérez-Torres, M., Ray, T.P., Riseley, C.J., Rowlinson, A., Shulevski, A., Sweijen, F., Timmerman, R., Vaccari, M., and Zheng, J.

Abstract

Contains fulltext : 290183.pdf (Publisher’s version ) (Open Access)

Published
2023

2. Shock imprints on the radio mini halo in RBS 797

Author

Bonafede, A., Gitti, M., La Bella, N., Biava, N., Ubertosi, F., Brunetti, G., Lusetti, G., Brienza, M., Riseley, C.J., Stuardi, C., Botteon, A., Ignesti, A., Röttgering, H., Weeren, R.J. van, Bonafede, A., Gitti, M., La Bella, N., Biava, N., Ubertosi, F., Brunetti, G., Lusetti, G., Brienza, M., Riseley, C.J., Stuardi, C., Botteon, A., Ignesti, A., Röttgering, H., and Weeren, R.J. van

Abstract

Contains fulltext : 299923.pdf (Publisher’s version ) (Open Access)

Published
2023

3. Possible discovery of Calvera's supernova remnant

Author

Arias de Saavedra Benitez, M., Botteon, A., Bassa, C.G., Jagt, S. van der, Weeren, R.J. van, O'Sullivan, S.P., Bosschaart, Q., Dullaart, R.S., Hardcastle, M.J., Hessels, J.W.T., Shimwell, T., Slob, M.M., Sturm, J.A., Tasse, C., Theijssen, N.C.M.A., Vink, J., High Energy Astrophys. & Astropart. Phys (API, FNWI), and Gravitation and Astroparticle Physics Amsterdam

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Pulsars: individual: 1RXS J141256.0+792204, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), H II regions, FOS: Physical sciences, Astronomy and Astrophysics, Surveys, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies, ISM: supernova remnants, ISM: general
Abstract

We report the discovery of a ring of low surface brightness radio emission around the Calvera pulsar, a high Galactic latitude, isolated neutron star, in the LOFAR Two-metre Sky Survey (LoTSS). It is centered at $\alpha=14\mathrm{h}11\mathrm{m}12.6\mathrm{s}$, $\delta=+79^\mathrm{o}23'15"$, has inner and outer radii of $14.2'$ and $28.4'$, and an integrated flux density at 144 MHz of $1.08\pm0.15$ Jy. The ring center is offset by $4.9'$ from the location of the Calvera pulsar. H$\alpha$ observations with the Isaac Newton Telescope show no coincident optical emission, but do show a small ($\sim20"$) optical structure internal to the ring. We consider three possible interpretations for the ring: that it is an H~II region, a supernova remnant (SNR), or an Odd Radio Circle (ORC). The positional coincidence of the ring, the pulsar, and an X-ray-emitting non-equilibrium ionisation plasma previously detected, lead us to prefer the SNR interpretation. If the source is indeed a SNR and its association with the Calvera pulsar is confirmed, then Calvera's SNR, or G118.4+37.0, will be one of few SNRs in the Galactic halo., Comment: Accepted in A&A

Published
2022

4. Using the polarization properties of double radio relics to probe the turbulent compression scenario

Author

Stuardi, C., Bonafede, A., Rajpurohit, K., Brüggen, M., de Gasperin, F., Hoang, D., Weeren, R.J. van, and Vazza, F.

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), FOS: Physical sciences, Astronomy and Astrophysics, ZwCl 2341+0000, galaxies, Astrophysics::Cosmology and Extragalactic Astrophysics, magnetic fields, 8C 0212+703, galaxies, Abell 3365, magnetic fields, galaxies, Space and Planetary Science, Abell 3365, galaxies, ZwCl 2341+0000, 8C 0212+703, PLCK G287.0+32.9, intracluster medium, Astrophysics - Cosmology and Nongalactic Astrophysics, clusters, individual, intracluster medium, PLCK G287.0+32.9, galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Radio relics are Mpc-size synchrotron sources located in the outskirts of some merging galaxy clusters. Binary-merging systems with favorable orientation may host two almost symmetric relics, named double radio relics. Double radio relics are seen preferentially edge-on and, thus, constitute a privileged sample for statistical studies. Their polarization and Faraday rotation properties give direct access to the relics origin and magnetic fields. In this paper, we present a polarization and Rotation Measure (RM) synthesis study of four clusters hosting double radio relics, namely 8C 0212+703, Abell 3365, PLCK G287.0+32.9, previously missing polarization studies, and ZwCl 2341+0000, for which conflicting results have been reported. We used 1-2 GHz Karl G. Jansky Very Large Array observations. We also provide an updated compilation of known double radio relics with important observed quantities. We studied their polarization and Faraday rotation properties at 1.4 GHz and we searched for correlations between fractional polarization and physical resolution, distance from the cluster center, and shock Mach number. The weak correlations found between these quantities are well reproduced by state-of-the-art magneto-hydrodynamical simulations of radio relics, confirming that merger shock waves propagate in a turbulent medium with tangled magnetic fields. Both external and internal Faraday depolarization should play a fundamental role in determining the polarization properties of radio relics at 1.4 GHz. Although the number of double radio relics with RM information is still low, their Faraday rotation properties (i.e., rest-frame RM and RM dispersion below 40 rad m$^{-2}$ and non-Gaussian RM distribution) can be explained in the scenario in which shock waves with Mach numbers larger than 2.5 propagate along the plane of the sky and compress the turbulent intra-cluster medium., 23 pages, 5 tables, 14 Figures, 1 appendix, accepted for publication by A&A

Published
2022

5. CHANG-ES XXIII: Influence of a galactic wind in NGC 5775

Author

Heald, G.H., Heesen, V., Sridhar, S.S., Beck, R., Bomans, D.J., Brüggen, M., Chyży, K.T., Damas-Segovia, A., Dettmar, R.-J., English, J., Henriksen, R., Ideguchi, S., Irwin, J., Vortmeyer-Krause, M., Li, J.-T., Murphy, E.J., Nikiel-Wroczyński, B., Piotrowska, J., Rand, R.J., Shimwell, T., Stein, Y., Vargas, C.J., Wang, Q.D., Weeren, R.J. van, Wiegert, T., Heald, G.H., Heesen, V., Sridhar, S.S., Beck, R., Bomans, D.J., Brüggen, M., Chyży, K.T., Damas-Segovia, A., Dettmar, R.-J., English, J., Henriksen, R., Ideguchi, S., Irwin, J., Vortmeyer-Krause, M., Li, J.-T., Murphy, E.J., Nikiel-Wroczyński, B., Piotrowska, J., Rand, R.J., Shimwell, T., Stein, Y., Vargas, C.J., Wang, Q.D., Weeren, R.J. van, and Wiegert, T.

Abstract

Contains fulltext : 240247.pdf (Publisher’s version ) (Open Access)

Published
2022

6. Filamentary structures of ionized gas in Cygnus X

Author

Emig, K.L., White, G.J., Salas, P., Karim, R.L., Weeren, R.J. van, Teuben, P.J., Haverkorn, M., Polderman, I.M., Rottgering, H.J.A., Tielens, A.G.G.M., Emig, K.L., White, G.J., Salas, P., Karim, R.L., Weeren, R.J. van, Teuben, P.J., Haverkorn, M., Polderman, I.M., Rottgering, H.J.A., and Tielens, A.G.G.M.

Abstract

Contains fulltext : 253316.pdf (Publisher’s version ) (Open Access)

Published
2022

7. The detection of cluster magnetic fields via radio source depolarisation

Author

Osinga, E., Weeren, R.J. van, Andrade-Santos, F., Rudnick, L., Bonafede, A., Clarke, T., Duncan, K., Giacintucci, S., Mroczkowski, T., and Röttgering, H.J.A.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), polarization, Cosmology and Nongalactic Astrophysics (astro-ph.CO), FOS: Physical sciences, Astronomy and Astrophysics, magnetic fields, magnetic fields, polarization, galaxies, Astrophysics - Astrophysics of Galaxies, methods, non-thermal, radiation mechanisms, Space and Planetary Science, general, Astrophysics of Galaxies (astro-ph.GA), galaxies, non-thermal, methods, clusters, observational, intracluster medium, radiation mechanisms, observational, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena, general, galaxies, Astrophysics - High Energy Astrophysical Phenomena, intracluster medium, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

It has been well established that galaxy clusters have magnetic fields. The exact properties and origin of these magnetic fields are still uncertain even though these fields play a key role in many astrophysical processes. Various attempts have been made to derive the magnetic field strength and structure of nearby galaxy clusters using Faraday rotation of extended cluster radio sources. This approach needs to make various assumptions that could be circumvented when using background radio sources. However, because the number of polarised radio sources behind clusters is low, at the moment such a study can only be done statistically. In this paper, we investigate the depolarisation of radio sources inside and behind clusters in a sample of 124 massive clusters at $z, Replaced with Published version (A&A). 32 pages, 34 figures

Published
2022

8. The Planck clusters in the LOFAR sky. I. LoTSS-DR2

Author

Botteon, A., Shimwell, T.W., Cassano, R., Cuciti, V., Zhang, X., Bruno, L., Camillini, L., Natale, R., Jones, A., Gastaldello, F., Simionescu, A., Rossetti, M., Akamatsu, H., Weeren, R.J. van, Brunetti, G., Brüggen, M., Groeneveld, C., Hoang, D.N., Hardcastle, M.J., Ignesti, A., Di Gennaro, G., Bonafede, A., Drabent, A., Röttgering, H.J.A., Hoeft, M., and de Gasperin, F.

Subjects
Astrophysics - cosmology and nongalactic astrophysics, Radiation mechanisms - non-thermal, Galaxies - clusters - general, Catalogs, Galaxies - clusters - intracluster medium, Radiation mechanisms - thermal, Astrophysics - high energy astrophysical phenomena
Published
2022

10. Deep Chandra observations of double relic cluster ZwCl 2341+0000

Author

Zhang, X., Simionescu, A., Stuardi, C., Weeren, R.J. van, Intema, H.T., Akamatsu, H., Plaa, J. de, Kaastra, J., Bonafede, A., Brüggen, M., Zuhone, J., and Ichinohe, Y.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Galaxy cluster gormation, Astrophysics::Cosmology and Extragalactic Astrophysics, Zenodo community gcf2021, Astrophysics::Galaxy Astrophysics
Abstract

We present the results of deep Chandra observations of ZwCl 2341+0000, which is a merging galaxy cluster hosting double radio relics. Previous X-ray investigation found an X-ray surface brightness discontinuity that is only associated with a part of the southern radio relic, posing questions for shock acceleration as the mechanism of the origin of radio relics. Using deep Chandra observations, we find that this jump is a core-remnant cold front associated with the southern subcluster. The actual location of the southern shock front is at the southeastern edge of the southern relic, which is unveiled by the radio spectral index map calculated using new GMRT 325 MHz and JVLA 1.5 GHz images. The deep Chandra observations also serendipitously reveal several intriguing features, for example, a cone shaped northern subcluster, a 400 kpc straight gas trail stripped from the cone apex, a peculiar high temperature region between the two subclusters that doesn't hold pressure equilibrium with the ambient gas. The conic subcluster is a unique feature that has never been observed before. We look up analogies for the conic subcluster in numerical simulations and find that a cone shape represents a certain stage during the remnant core travelling outbound. The drop of the pressure in the outskirts makes the front side of the remnant core quickly expand, which distorts a blunt body cold front into a cone. The simulation also reproduces an observed feature that the gas distribution inside the cone is inhomogeneous, meaning that the boundary of the cone has a higher density than that inside the cone. The new findings improve the knowledge of the evolution of remnant core in head-on mergers.

Published
2021

11. Dissecting nonthermal emission in the complex multiple-merger galaxy cluster Abell 274: radio and X-ray analysis

Author

Rajpurohit, K., Vazza, F., Weeren, R.J. van, Hoeft, M., Brienza, M., Bonnassieux, E., Riseley, C.J., Brunetti, G., Bonafede, A., Brüggen, M., Formann, W.R., Rajpurohit, A.S., Rottgering, H.J.A., Drabent, A., Domínguez-Fernández, P., Wittor, D., and Andrade-Santos, F.

Subjects
Clusters, Radio Continuum, Thermal, Radiation Mechanisms, Acceleration of Particles, Individual, Star Clusters, Abell 2744, Galaxies, General, Non-Thermal, Astrophysics - Cosmology and Nongalactic Astrophysics
Published
2021

12. High dynamic range JVLA observations of Perseus Cluster Radio Galaxies

Author

Gendron Marsolais, M., Hlavacek Larrondo, J., Hull, C., Perley, R., Rudnick, L., Kraft, R., Fabian, A.C., Roediger, E., Weeren, R.J. van, Richard Laferrière, A., Arakawa, N., Clarke, T.E., Sebastian, B., Mroczkowski, T., Sheldahl, E., Blundell, K., Nyland, K., Sanders, J., Peters, W., and Intema, H.T.

Published
2021

14. Erratum: LoTSS jellyfish galaxies: I. radio tails in low redshift clusters

Author

Roberts, I.D., Weeren, R.J. van, McGee, S.L., Botteon, A., Drabent, A., Ignesti, A., Rottgering, H.J.A., Shimwell, T.W., and Tasse, C.

Subjects
Clusters, Addenda, Radio Continuum, Errata, Evolution, Irregular, Galaxies, General
Abstract

Erratum for: A&A 650, A111 (2021), https://doi.org/10.1051/0004-6361/202140784

Published
2021

15. Discovery of a radio halo (and relic) in a M_500 < 2x10^14 M sun cluster

Author

Botteon, A., Cassano, R., Weeren, R.J. van, Shimwell, T.W., Bonafede, A., Brüggen, M., Brunetti, G., Cuciti, V., Dallacasa, D., Gasperin, F. de, Di Gennaro, G., Gastaldello, F., Hoang, D.N., Rossetti, M., and Rottgering, H.J.A.

Subjects
Non-thermal radiation sources, Astrophysics - cosmology and nongalactic astrophysics, Astrophysics - astrophysics of galaxies, Galaxy clusters, Astrophysics - high energy astrophysical phenomena, Intracluster medium, 584, 858, 508, 1338, 1346, 504, 1119, Extragalactic radio sources, Radio interferometry, Radio astronomy, Extended radiation sources
Published
2021

16. A giant radio bridge connecting two galaxy clusters in Abell 1758

Author

Botteon, A., Weeren, R.J. van, Brunetti, G., Gasperin, F. de, Intema, H.T., Osinga, E., Di Gennaro, G., Shimwell, T.W., Bonafede, A., Brüggen, M., Cassano, R., Cuciti, V., Dallacasa, D., Gastaldello, F., Mandal, S., Rossetti, M., Rottgering, H.J.A., Botteon A., Van Weeren R.J., Brunetti G., De Gasperin F., Intema H.T., Osinga E., Di Gennaro G., Shimwell T.W., Bonafede A., Bruggen M., Cassano R., Cuciti V., Dallacasa D., Gastaldello F., Mandal S., Rossetti M., and Rottgering H.J.A.

Subjects
galaxies: clusters: intracluster medium, Radiation mechanisms: non-thermal, galaxies: clusters: general, Astrophysics::High Energy Astrophysical Phenomena, galaxies: clusters: individual: A1758, radio continuum: general, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Collisions between galaxy clusters dissipate enormous amounts of energy in the intracluster medium (ICM) through turbulence and shocks. In the process, Mpc-scale diffuse synchrotron emission in form of radio haloes and relics can form. However, little is known about the very early phase of the collision. We used deep radio observations from 53 MHz to 1.5 GHz to study the pre-merging galaxy clusters A1758N and A1758S that are ∼2 Mpc apart. We confirm the presence of a giant bridge of radio emission connecting the two systems that was reported only tentatively in our earlier work. This is the second large-scale radio bridge observed to date in a cluster pair. The bridge is clearly visible in the LOFAR image at 144 MHz and tentatively detected at 53 MHz. Its mean radio emissivity is more than one order of magnitude lower than that of the radio haloes in A1758N and A1758S. Interestingly, the radio and X-ray emissions of the bridge are correlated. Our results indicate that non-thermal phenomena in the ICM can be generated also in the region of compressed gas in-between infalling systems.

Published
2020

17. Probing the non-thermal emission in the Perseus cluster with the JVLA

Author

Gendron-Marsolais, M., Hlavacek-Larrondo, J., Weeren, R.J. van, Clarke, T., Fabian, A.C., Intema, H.T., Taylor, G.B., Blundell, K.M., Sanders, J.S., Asada, K., de Gouveia Dal Pino, E., Giroletti, M., Nagai, H., and Nemmen, R.

Subjects
Very large array, Physics, education.field_of_study, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Perseus Cluster, Population, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Thermal emission, Astrophysics, 01 natural sciences, Jansky, Radio relics, Space and Planetary Science, 0103 physical sciences, Cluster (physics), Radio frequency, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract

We present deep low radio frequency (230-470 MHz) observations from the Karl G. Jansky Very Large Array of the Perseus cluster, probing the non-thermal emission from the old particle population of the AGN outflows. Our observations of this nearby relaxed cool core cluster have revealed a multitude of new structures associated with the mini-halo, extending to hundreds of kpc in size. Its irregular morphology seems to have been influenced both by the AGN activity and by the sloshing motion of the cluster’ gas. In addition, it has a filamentary structure similar to that seen in radio relics found in merging clusters. These results illustrate the high-quality images that can be obtained with the new JVLA at low radio-frequencies.

Published
2018

19. The Future Landscape of High-Redshift Galaxy Cluster Science

Author

Mantz, A., Allen, S.W., Battaglia, N., Benson, B., Canning, R., Ettori, S., Evrard, A., Linden, A., McDonald, M., Abidi, M., Ahmed, Z., Amin, Mustafa.A., Ansarinejad, B., Armstrong, R., Avestruz, C., Baccigalupi, C., Bandura, K., Barkhouse, W., Basu, K., Bavdhankar, C., Bender, A.N., Bernardis, P., Bischoff, C., Biviano, A., Bleem, L., Bocquet, S., Bond, J., Borgani, S., Borrill, J., Boutigny, D., Frye, B., Bruggen, M., Cai, Z., Carlstrom, J.E., Castander, F.J., Challinor, A., Clowe, D., Cohn, J.D., Comparat, J., Cooray, A., Coulton, W., Cyr-Racine, F., Daddi, E., Delabrouille, J., Dell'antonio, I., Demarteau, M., Donahue, M., Dunkley, J., Escoffier, S., Essinger-Hileman, T., Fabbian, G., Fabjan, D., Farahi, A., Foreman, S., Fraisse, A.A., Garcia, L., Gaspari, M., Gerbino, M., Gitti, M., Gluscevic, V., Gonzalez, A., Górski, K.M., Gruen, D., Gudmundsson, J.E., Gupta, N., Haan, T., Hernquist, L., Hirata, C.M., Hlozek, R., Jeltema, T., Cohen-Tanugi, J., Johnson, B., Kadota, K., Kamionkowski, M., Khatri, R., Kisner, T., Kneib, J., Knox, L., Kovetz, E.D., Krause, E., Lattanzi, M., Lau, Erwin.T., Liguori, M., Lovisari, L., Macorra, A., Masi, S., Masui, K., Maughan, B., Maurogordato, S., McMahon, J., McNamara, B., Melchior, P., Mertens, J., Meyers, J., Mirbabayi, M., More, S., Motloch, P., Moustakas, J., Mroczkowski, T., Mukherjee, S., Nagai, D., Nagy, J., Naselsky, P., Nati, F., Newburgh, L., Niemack, M.D., Nomerotski, A., Noordeh, E., Ntampaka, M., Ota, N., Page, L., Palmese, A., Penna-Lima, M., Piacentni, F., Pierpaoli, E., Plazas, A.A., Pogosian, L., Pointecouteau, E., Prakash, A., Pratt, G., Prescod-Weinstein, C., Pryke, C., Puglisi, G., Rapetti, D., Raveri, M., Reichardt, C.L., Reiprich, Thomas.H., Remazeilles, M., Rhodes, J., Ricci, M., Rocha, G., Rose, B., Rozo, E., Ruhl, J., Sadun, A., Saliwanchik, B., Schaan, E., Schmidt, R., Fromenteau, S., Sehgal, N., Senatore, L., Seo, H., Sereno, M., Shafieloo, A., Shan, H., Shandera, S., Sherwin, B.D., Simon, S., Sridhar, S., Staggs, S., Stern, D., Suzuki, A., Tsai, Y., Turriziani, S., Umilta, C., Vazza, F., Vieregg, A., Vikhlinin, A., Walker, S.A., Watson, S., Weeren, R.J. van, Weller, J., Werner, N., Whitehorn, N., Wong, K., Wright, A., Wu, W.L.K., Xu, Z., Yasini, S., Zemcov, M., Zhang, Y., Zhao, G., Zheng, Y., Zhu, N., Zhuravleva, I., Zuntz, J., Hickox, R., Churazov, E., Nulsen, P., Jones, W.C., Wang, L., and Desai, S.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We describe the opportunities for galaxy cluster science in the high- redshift regime where massive, virialized halos first formed and where star formation and AGN activity peaked. New observing facilities from radio to X-ray wavelengths, combining high spatial/spectral resolution with large collecting areas, are poised to uncover this population.

Published
2019

20. Low-frequency radio absorption in Cassiopeia A

Author

Arias, M., Vink, J., Gasperin, F. de, Salas, P., Oonk, J.B.R., Weeren, R.J. van, Horandel, J., Zarka, P., Zucca, P., Arias, M., Vink, J., Gasperin, F. de, Salas, P., Oonk, J.B.R., Weeren, R.J. van, Horandel, J., Zarka, P., and Zucca, P.

Abstract

Contains fulltext : 191392.pdf (preprint version ) (Open Access)

Published
2018

21. LOFAR discovery of radio emission in MACS J0717.5+3745

Author

Bonafede, A., Brueggen, M., Rafferty, D., Zhuravleva, I., Riseley, C.J., Weeren, R.J. van, Farnes, J.S., Orru, E., Rottgering, H.J.A., Shimwell, T.W., Bonafede, A., Brueggen, M., Rafferty, D., Zhuravleva, I., Riseley, C.J., Weeren, R.J. van, Farnes, J.S., Orru, E., Rottgering, H.J.A., and Shimwell, T.W.

Abstract

Contains fulltext : 194861.pdf (publisher's version ) (Closed access)

Published
2018

22. Deep LOFAR observations of the merging galaxy cluster CIZA J2242.8+5301

Author

Hoang, D.N., Shimwell, T.W., Stroe, A., Akamatsu, H., Brunetti, G., Donnert, J.M.F., Intema, H.T., Mulcahy, D.D., Röttgering, H.J.A., Weeren, R.J. van, Bonafede, A., Brüggen, M., Cassano, R., Chyży, K.T., Enßlin, T., Ferrari, C., Gasperin, F. de, Gu, L., Hoeft, M., Miley, G.K., Orru, E., Pizzo, R., White, G.J., Hoang, D.N., Shimwell, T.W., Stroe, A., Akamatsu, H., Brunetti, G., Donnert, J.M.F., Intema, H.T., Mulcahy, D.D., Röttgering, H.J.A., Weeren, R.J. van, Bonafede, A., Brüggen, M., Cassano, R., Chyży, K.T., Enßlin, T., Ferrari, C., Gasperin, F. de, Gu, L., Hoeft, M., Miley, G.K., Orru, E., Pizzo, R., and White, G.J.

Abstract

Contains fulltext : 176380.pdf (publisher's version ) (Open Access)

Published
2017

23. LOFAR MSSS: Discovery of a 2.56 Mpc giant radio galaxy associated with a disturbed galaxy group

Author

Clarke, A.O., Heald, G., Jarrett, T., Bray, J.D., Hardcastle, M.J., Cantwell, T.M., Scaife, A.M.M., Brienza, M., Bonafede, A., Breton, R.P., Broderick, J.W., Carbone, D., Croston, J.H., Farnes, J.S., Harwood, J.J., Heesen, V., Horneffer, A., Horst, A.J. van der, Iacobelli, M., Jurusik, W., Kokotanekov, G., McKean, J.P., Morabito, L.K., Mulcahy, D.D., Nikiel-Wroczyñski, B.S., Orrú, E., Paladino, R., Pandey-Pommier, M., Pietka, M., Pizzo, R., Pratley, L., Riseley, C.J., Rottgering, H.J.A., Rowlinson, A., Sabater, J., Sendlinger, K., Shulevski, A., Sridhar, S.S., Stewart, A.J., Tasse, C., Velzen, S. van, Weeren, R.J. van, Wise, M.W., Clarke, A.O., Heald, G., Jarrett, T., Bray, J.D., Hardcastle, M.J., Cantwell, T.M., Scaife, A.M.M., Brienza, M., Bonafede, A., Breton, R.P., Broderick, J.W., Carbone, D., Croston, J.H., Farnes, J.S., Harwood, J.J., Heesen, V., Horneffer, A., Horst, A.J. van der, Iacobelli, M., Jurusik, W., Kokotanekov, G., McKean, J.P., Morabito, L.K., Mulcahy, D.D., Nikiel-Wroczyñski, B.S., Orrú, E., Paladino, R., Pandey-Pommier, M., Pietka, M., Pizzo, R., Pratley, L., Riseley, C.J., Rottgering, H.J.A., Rowlinson, A., Sabater, J., Sendlinger, K., Shulevski, A., Sridhar, S.S., Stewart, A.J., Tasse, C., Velzen, S. van, Weeren, R.J. van, and Wise, M.W.

Abstract

Contains fulltext : 173529.pdf (preprint version ) (Open Access)

Published
2017

24. LOFAR MSSS: The scaling relation between AGN cavity power and radio luminosity at low radio frequencies

Author

Kokotanekov, G., Wise, M., Heald, G.H., McKean, J.P., Birzan, L., Rafferty, D.A., Godfrey, L.E.H., Vries, M de, Intema, H.T., Broderick, J.W., Hardcastle, M.J., Bonafede, A., Clarke, A.O., Weeren, R.J. van, Rottgering, H.J.A., Pizzo, R., Iacobelli, M., Orru, E., Shulevski, A., Riseley, C.J., Breton, R.P., Nikiel-Wroczynski, B., Sridhar, S.S., Stewart, A.J., Rowlinson, A., Horst, A.J. van der, Harwood, J.J., Gurkan, G., Carbone, D., Pandey-Pommier, M., Tasse, C., Scaife, A.M.M., Pratley, L., Ferrari, C., Croston, J.H., Pandey, V.N., Jurusik, W., Mulcahy, D.D., Kokotanekov, G., Wise, M., Heald, G.H., McKean, J.P., Birzan, L., Rafferty, D.A., Godfrey, L.E.H., Vries, M de, Intema, H.T., Broderick, J.W., Hardcastle, M.J., Bonafede, A., Clarke, A.O., Weeren, R.J. van, Rottgering, H.J.A., Pizzo, R., Iacobelli, M., Orru, E., Shulevski, A., Riseley, C.J., Breton, R.P., Nikiel-Wroczynski, B., Sridhar, S.S., Stewart, A.J., Rowlinson, A., Horst, A.J. van der, Harwood, J.J., Gurkan, G., Carbone, D., Pandey-Pommier, M., Tasse, C., Scaife, A.M.M., Pratley, L., Ferrari, C., Croston, J.H., Pandey, V.N., Jurusik, W., and Mulcahy, D.D.

Abstract

Contains fulltext : 178435.pdf (preprint version ) (Open Access)

Published
2017

25. The association of a J-burst with a solar jet⋆

Author

Morosan, D.E., Gallagher, P.T., Fallows, R.A., Reid, H., Mann, G., Bisi, M.M., Magdalenić, J., Rucker, H.O., Thidé, B., Vocks, C., Anderson, J., Asgekar, A., Avruch, I.M., Bell, M.E., Bentum, M.J., Best, P., Blaauw, R., Bonafede, A., Breitling, F., Broderick, J.W., Brüggen, M., Cerrigone, L., Ciardi, B., Geus, E. de, Duscha, S., Eislöffel, J., Falcke, H., Garrett, M.A., Grießmeier, J.M., Gunst, A.W., Hoeft, M., Iacobelli, M., Juette, E., Kuper, G., McFadden, R., McKay-Bukowski, D., McKean, J.P., Mulcahy, D.D., Munk, H., Nelles, A., Orru, E., Paas, H., Pandey-Pommier, M., Pandey, V.N., Pizzo, R., Polatidis, A.G., Reich, W., Schwarz, D.J., Sluman, J., Smirnov, O., Steinmetz, M., Tagger, M., Veen, S ter, Thoudam, S., Toribio, M.C., Vermeulen, R., Weeren, R.J. van, Wucknitz, O., Zarka, P., Morosan, D.E., Gallagher, P.T., Fallows, R.A., Reid, H., Mann, G., Bisi, M.M., Magdalenić, J., Rucker, H.O., Thidé, B., Vocks, C., Anderson, J., Asgekar, A., Avruch, I.M., Bell, M.E., Bentum, M.J., Best, P., Blaauw, R., Bonafede, A., Breitling, F., Broderick, J.W., Brüggen, M., Cerrigone, L., Ciardi, B., Geus, E. de, Duscha, S., Eislöffel, J., Falcke, H., Garrett, M.A., Grießmeier, J.M., Gunst, A.W., Hoeft, M., Iacobelli, M., Juette, E., Kuper, G., McFadden, R., McKay-Bukowski, D., McKean, J.P., Mulcahy, D.D., Munk, H., Nelles, A., Orru, E., Paas, H., Pandey-Pommier, M., Pandey, V.N., Pizzo, R., Polatidis, A.G., Reich, W., Schwarz, D.J., Sluman, J., Smirnov, O., Steinmetz, M., Tagger, M., Veen, S ter, Thoudam, S., Toribio, M.C., Vermeulen, R., Weeren, R.J. van, Wucknitz, O., and Zarka, P.

Abstract

Contains fulltext : 178482.pdf (publisher's version ) (Open Access)

Published
2017

26. LOFAR 150-MHz observations of the Boötes field: Catalogue and Source Counts

Author

Wiliams, W.L., Weeren, R.J. van, Röttgering, H.J.A., Best, P., Dijkema, T.J., Gasperin, F. de, Hardcastle, M.J., Heald, G., Prandoni, I., Sabater, J., Shimwell, T.W., Tasse, C., Bemmel, I.M. van, Brüggen, M., Brunetti, G., Conway, J.E., Enßlin, T., Engels, D., Falcke, H., Ferrari, C., Haverkorn, M., Jackson, N., Jarvis, M.J., Kapińska, A.D., Mahony, E.K., Miley, G.K., Morabito, L.K., Morganti, R., Orrú, E., Retana-Montenegro, E., Sridhar, S.S., Toribio, M.C., White, G.J., Wise, M.W., Zwart, J.T.L., Wiliams, W.L., Weeren, R.J. van, Röttgering, H.J.A., Best, P., Dijkema, T.J., Gasperin, F. de, Hardcastle, M.J., Heald, G., Prandoni, I., Sabater, J., Shimwell, T.W., Tasse, C., Bemmel, I.M. van, Brüggen, M., Brunetti, G., Conway, J.E., Enßlin, T., Engels, D., Falcke, H., Ferrari, C., Haverkorn, M., Jackson, N., Jarvis, M.J., Kapińska, A.D., Mahony, E.K., Miley, G.K., Morabito, L.K., Morganti, R., Orrú, E., Retana-Montenegro, E., Sridhar, S.S., Toribio, M.C., White, G.J., Wise, M.W., and Zwart, J.T.L.

Abstract

Contains fulltext : 159656.pdf (preprint version ) (Open Access)

Published
2016

27. A plethora of diffuse steep spectrum radio sources in Abell 2034 revealed by LOFAR

Author

Shimwell, T.W., Luckin, J., Brüggen, M., Brunetti, G., Intema, H.T., Owers, M.S., Röttgering, H.J.A., Stroe, A., Weeren, R.J. van, Williams, W.L., Cassano, R., Gasperin, F. de, Heald, G.H., Hoang, D.N., Hardcastle, M.J., Sridhar, S.S., Sabater, J., Best, P.N., Bonafede, A., Chyży, K.T., Enßlin, T.A., Ferrari, C., Haverkorn, M., Hoeft, M., Horellou, C., McKean, J.P., Morabito, L.K., Orrù, E., Pizzo, R., Retana-Montenegro, E., White, G.J., Shimwell, T.W., Luckin, J., Brüggen, M., Brunetti, G., Intema, H.T., Owers, M.S., Röttgering, H.J.A., Stroe, A., Weeren, R.J. van, Williams, W.L., Cassano, R., Gasperin, F. de, Heald, G.H., Hoang, D.N., Hardcastle, M.J., Sridhar, S.S., Sabater, J., Best, P.N., Bonafede, A., Chyży, K.T., Enßlin, T.A., Ferrari, C., Haverkorn, M., Hoeft, M., Horellou, C., McKean, J.P., Morabito, L.K., Orrù, E., Pizzo, R., Retana-Montenegro, E., and White, G.J.

Abstract

Contains fulltext : 159669.pdf (preprint version ) (Open Access)

Published
2016

28. LOFAR MSSS: detection of a low-frequency radio transient in 400 h of monitoring of the North Celestial Pole

Author

Stewart, A.J., Fender, R.P., Broderick, J.W., Hassall, T.E., Muñoz-Darias, T., Rowlinson, A., Swinbank, J.D., Staley, T.D., Molenaar, G.J., Scheers, B., Grobler, T.L., Pietka, M., Heald, G., McKean, J.P., Bell, M.E., Bonafede, A., Breton, R.P., Carbone, D., Cendes, Y., Clarke, A.O., Corbel, S., Gasperin, F. de, Eislöffel, J., Falcke, H., Ferrari, C., Grießmeier, J.-M., Hardcastle, M.J., Heesen, V., Hessels, J.W.T., Horneffer, A., Iacobelli, M., Jonker, P.G., Karastergiou, A., Kokotanekov, G., Kondratiev, V.I., Kuniyoshi, M., Law, C.J., Leeuwen, J. van, Markoff, S., Miller-Jones, J.C.A., Mulcahy, D., Orru, E., Pandey-Pommier, M., Pratley, L., Rol, E., Röttgering, H.J.A., Scaife, A.M.M., Shulevski, A., Sobey, C.A., Stappers, B.W., Tasse, C., Horst, A.J. van der, Velzen, S. van, Weeren, R.J. van, Wijers, R.A.M.J., Wijnands, R., Wise, M., Zarka, P., Alexov, A., Anderson, J., Asgekar, A., Avruch, I.M., Bentum, M.J., Bernardi, G., Best, P., Breitling, F., Brüggen, M., Butcher, H.R., Ciardi, B., Conway, J.E., Corstanje, A., Geus, A. de, Deller, A., Duscha, S., Frieswijk, W., Garrett, M.A., Gunst, A.W., Haarlem, M.P. van, Hoeft, M., Hörandel, J., Juette, E., Kuper, G., Loose, M., Maat, P., McFadden, R., McKay-Bukowski, D., Moldon, J., Munk, H., Norden, M.J., Paas, H., Polatidis, A.G., Schwarz, D., Sluman, J., Smirnov, O., Steinmetz, M., Thoudam, S., Toribio, M.C., Vermeulen, R., Vocks, C., Wijnholds, S.J., Wucknitz, O., Yatawatta, S., Stewart, A.J., Fender, R.P., Broderick, J.W., Hassall, T.E., Muñoz-Darias, T., Rowlinson, A., Swinbank, J.D., Staley, T.D., Molenaar, G.J., Scheers, B., Grobler, T.L., Pietka, M., Heald, G., McKean, J.P., Bell, M.E., Bonafede, A., Breton, R.P., Carbone, D., Cendes, Y., Clarke, A.O., Corbel, S., Gasperin, F. de, Eislöffel, J., Falcke, H., Ferrari, C., Grießmeier, J.-M., Hardcastle, M.J., Heesen, V., Hessels, J.W.T., Horneffer, A., Iacobelli, M., Jonker, P.G., Karastergiou, A., Kokotanekov, G., Kondratiev, V.I., Kuniyoshi, M., Law, C.J., Leeuwen, J. van, Markoff, S., Miller-Jones, J.C.A., Mulcahy, D., Orru, E., Pandey-Pommier, M., Pratley, L., Rol, E., Röttgering, H.J.A., Scaife, A.M.M., Shulevski, A., Sobey, C.A., Stappers, B.W., Tasse, C., Horst, A.J. van der, Velzen, S. van, Weeren, R.J. van, Wijers, R.A.M.J., Wijnands, R., Wise, M., Zarka, P., Alexov, A., Anderson, J., Asgekar, A., Avruch, I.M., Bentum, M.J., Bernardi, G., Best, P., Breitling, F., Brüggen, M., Butcher, H.R., Ciardi, B., Conway, J.E., Corstanje, A., Geus, A. de, Deller, A., Duscha, S., Frieswijk, W., Garrett, M.A., Gunst, A.W., Haarlem, M.P. van, Hoeft, M., Hörandel, J., Juette, E., Kuper, G., Loose, M., Maat, P., McFadden, R., McKay-Bukowski, D., Moldon, J., Munk, H., Norden, M.J., Paas, H., Polatidis, A.G., Schwarz, D., Sluman, J., Smirnov, O., Steinmetz, M., Thoudam, S., Toribio, M.C., Vermeulen, R., Vocks, C., Wijnholds, S.J., Wucknitz, O., and Yatawatta, S.

Abstract

Contains fulltext : 155770.pdf (preprint version ) (Open Access)

Published
2016

29. LOFAR imaging of Cygnus A – Direct detection of a turnover in the hotspot radio spectra

Author

McKean, J.P., Godfrey, L.E.H., Vegetti, S., Wise, M.W., Morganti, R., Hardcastle, M.J., Rafferty, D., Anderson, J., Avruch, I.M., Beck, R., Bell, M.E., Bemmel, I. van, Bentum, M.J., Bernardi, G., Best, P., Blaauw, R., Bonafede, A., Breitling, F., Broderick, J.W., Brüggen, M., Cerrigone, L., Ciardi, B., Gasperin, F. de, Deller, A., Duscha, S., Engels, D., Falcke, H., Fallows, R.A., Frieswijk, W., Garrett, M.A., Grießmeier, J.M., Haarlem, M.P. van, Heald, G., Hoeft, M., Horst, A.J. van der, Iacobelli, M., Intema, H., Juette, E., Karastergiou, A., Kondratiev, V.I., Koopmans, L.V.E., Kuniyoshi, M., Kuper, G., Leeuwen, J. van, Maat, P., Mann, G., Markoff, S., McFadden, R., McKay-Bukowski, D., Mulcahy, D.D., Munk, H., Nelles, A., Orru, E., Paas, H., Pandey-Pommier, M., Pietka, M., Pizzo, R., Polatidis, A.G., Reich, W., Röttgering, H.J.A., Rowlinson, A., Scaife, A.M.M., Serylak, M, Shulevski, A., Sluman, J., Smirnov, O., Steinmetz, M., Stewart, A., Swinbank, J., Tagger, M., Thoudam, S., Toribio, M.C., Vermeulen, R., Vocks, C., Weeren, R.J. van, Wucknitz, O., Yatawatta, S., Zarka, P., McKean, J.P., Godfrey, L.E.H., Vegetti, S., Wise, M.W., Morganti, R., Hardcastle, M.J., Rafferty, D., Anderson, J., Avruch, I.M., Beck, R., Bell, M.E., Bemmel, I. van, Bentum, M.J., Bernardi, G., Best, P., Blaauw, R., Bonafede, A., Breitling, F., Broderick, J.W., Brüggen, M., Cerrigone, L., Ciardi, B., Gasperin, F. de, Deller, A., Duscha, S., Engels, D., Falcke, H., Fallows, R.A., Frieswijk, W., Garrett, M.A., Grießmeier, J.M., Haarlem, M.P. van, Heald, G., Hoeft, M., Horst, A.J. van der, Iacobelli, M., Intema, H., Juette, E., Karastergiou, A., Kondratiev, V.I., Koopmans, L.V.E., Kuniyoshi, M., Kuper, G., Leeuwen, J. van, Maat, P., Mann, G., Markoff, S., McFadden, R., McKay-Bukowski, D., Mulcahy, D.D., Munk, H., Nelles, A., Orru, E., Paas, H., Pandey-Pommier, M., Pietka, M., Pizzo, R., Polatidis, A.G., Reich, W., Röttgering, H.J.A., Rowlinson, A., Scaife, A.M.M., Serylak, M, Shulevski, A., Sluman, J., Smirnov, O., Steinmetz, M., Stewart, A., Swinbank, J., Tagger, M., Thoudam, S., Toribio, M.C., Vermeulen, R., Vocks, C., Weeren, R.J. van, Wucknitz, O., Yatawatta, S., and Zarka, P.

Abstract

Contains fulltext : 161143.pdf (preprint version ) (Open Access)

Published
2016

30. Radio emission from merging galaxy clusters : characterizing shocks, magnetic fields and particle acceleration

Author

Weeren, R.J. van, Röttgering, H.J.A., Miley, G.K., and Leiden University

Subjects
Radio continuum, Actvie galaxies, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Galaxy clusters, Astrophysics::Cosmology and Extragalactic Astrophysics, Large-scale structure of the Universe, Astrophysics::Galaxy Astrophysics
Abstract

In this thesis an interferometric study of diffuse radio sources, so-called halos and relics, in and around galaxy clusters is performed. These sources are thought to trace shocks and turbulence generated by galaxy cluster merger events. GMRT, WSRT and VLA observations are analyzed to measure the spectral and polarimetric properties of the diffuse cluster emission. In addition, a search for new relics and halos is carried out based on existing radio surveys. Numerical simulations of cluster mergers are described, which have the aim of constraining the cluster mergers parameters from observations of double radio relics. The first LOFAR observation of cluster-scale diffuse radio emission is presented. LOFAR is a new pan-European radio telescope that operates at the lowest radio frequencies accessible from the surface of the Earth.

Published
2011

32. LOFAR detections of low-frequency radio recombination lines towards Cassiopeia A

Author

Asgekar, A., Oonk, J.B., Yatawatta, S., Weeren, R.J. van, McKean, J.P., White, G., Jackson, N., Anderson, J., Avruch, I.M., Batejat, F., Beck, R., Bell, M.E., Bell, M.R. (Michael), Bemmel, I. van, Bentum, M.J., Bernardi, G., Best, P., Birzan, L., Bonafede, A., Braun, R., Breitling, F., Brink, R.H. van de, Broderick, J.W., Brouw, W.N., Brüggen, M., Butcher, H.R., Cappellen, W. van, Ciardi, B., Conway, J.E., De Gasperin, F., Geus, E. de, Jong, A. de, Vos, M. de, Duscha, S., Eislöffel, J., Falcke, H., Fellows, R.A., Ferrari, C., Frieswijk, W., Garrett, M.A., Grießmeier, J.-M., Grit, T., Gunst, A.W., Hassall, T.E., Heald, G., Hessels, J.W.T., Hoeft, M., Iacobelli, M., Intema, H., Juette, E., Karastergiou, A., Kohler, J., Kondratiev, V.I., Kuniyoshi, M., Kuper, G., Law, C.J., Leeuwen, J. van, Maat, P., Macario, G., Mann, G., Markoff, S., McKay-Bukowski, D., Mevins, M., Miller-Jones, J.C.A., Mol, J.D., Morganti, R., Mulcahy, D.D., Munk, H., Norden, M.J., Orru, E., Paas, H., Pandey-Pommier, M., Pandey, V.N. (Varun), Pizzo, R., Polatidis, A.G., Reich, W., Röttgering, H.J.A., Scheers, L.H.A. (Bart), Schoenmakers, A., Sluman, J., Smirnov, O., Sobey, C.A., Steinmetz, M., Tagger, M., Tang, Y., Tasse, C., Vermeulen, R., Vocks, C., Wijers, R.A.M.J. (Ralph), Wise, M.W. (Michael), Wucknitz, O., Zarka, P., Leeuwen, J. (Joeri) van, Asgekar, A., Oonk, J.B., Yatawatta, S., Weeren, R.J. van, McKean, J.P., White, G., Jackson, N., Anderson, J., Avruch, I.M., Batejat, F., Beck, R., Bell, M.E., Bell, M.R. (Michael), Bemmel, I. van, Bentum, M.J., Bernardi, G., Best, P., Birzan, L., Bonafede, A., Braun, R., Breitling, F., Brink, R.H. van de, Broderick, J.W., Brouw, W.N., Brüggen, M., Butcher, H.R., Cappellen, W. van, Ciardi, B., Conway, J.E., De Gasperin, F., Geus, E. de, Jong, A. de, Vos, M. de, Duscha, S., Eislöffel, J., Falcke, H., Fellows, R.A., Ferrari, C., Frieswijk, W., Garrett, M.A., Grießmeier, J.-M., Grit, T., Gunst, A.W., Hassall, T.E., Heald, G., Hessels, J.W.T., Hoeft, M., Iacobelli, M., Intema, H., Juette, E., Karastergiou, A., Kohler, J., Kondratiev, V.I., Kuniyoshi, M., Kuper, G., Law, C.J., Leeuwen, J. van, Maat, P., Macario, G., Mann, G., Markoff, S., McKay-Bukowski, D., Mevins, M., Miller-Jones, J.C.A., Mol, J.D., Morganti, R., Mulcahy, D.D., Munk, H., Norden, M.J., Orru, E., Paas, H., Pandey-Pommier, M., Pandey, V.N. (Varun), Pizzo, R., Polatidis, A.G., Reich, W., Röttgering, H.J.A., Scheers, L.H.A. (Bart), Schoenmakers, A., Sluman, J., Smirnov, O., Sobey, C.A., Steinmetz, M., Tagger, M., Tang, Y., Tasse, C., Vermeulen, R., Vocks, C., Wijers, R.A.M.J. (Ralph), Wise, M.W. (Michael), Wucknitz, O., Zarka, P., and Leeuwen, J. (Joeri) van

Abstract

Cassiopeia A was observed using the low-band antennas of the LOw Frequency ARray (LOFAR) with high spectral resolution. This allowed a search for radio recombination lines (RRLs) along the line-of-sight to this source. Five carbon alpha RRLs were detected in absorption between 40 and 50 MHz with a signal-to-noise ratio of >5 from two independent LOFAR data sets. The derived line velocities (vLSR ~ - 50 km s-1) and integrated optical depths (~13 s-1) of the RRLs in our spectra, extracted over the whole supernova remnant, are consistent within each LOFAR data set and with those previously reported. For the first time, we are able to extract spectra against the brightest hotspot of the remnant at frequencies below 330 MHz. These spectra show significantly higher (15-80 percent) integrated optical depths, indicating that there is small-scale angular structure of the order of ~1 pc in the absorbing gas distribution over the face of the remnant. We also place an upper limit of 3 × 10-4 on the peak optical depths of hydrogen and helium RRLs. These results demonstrate that LOFAR has the desired spectral stability and sensitivity to study faint recombination lines in the decameter band.

Published
2013

34. A double radio relic in the merging galaxy cluster ZwCl 0008.8+5215

Author

Weeren, R.J. van, Hoeft, M., Rottgering, H.J.A., Bruggen, M., Intema, H.T., Velzen, S. van, Weeren, R.J. van, Hoeft, M., Rottgering, H.J.A., Bruggen, M., Intema, H.T., and Velzen, S. van

Abstract

Contains fulltext : 91496.pdf (preprint version ) (Open Access)

Published
2011

36. [Untitled]

Author

Brandl, B.R., Burtscher, L.H., Brinchmann, J., Snellen, I.A.G., Werf, P.P. van der, Kaastra, J.S., Weeren, R.J. van, Morganti, R., Davies, R.I., and Leiden University

Subjects
Active galactic nuclei, Galaxy Clusters, Galaxy Evolution, Bulge, AGN, Galaxies
Abstract

The origin and evolution of galaxies are closely linked to many different physical phenomena. Among them, the most important one is the environment they reside in. Isolated and cluster member galaxies indeed are affected by different forces which affect their evolution. The main concern of this thesis is to understand such forces and how they are related to galaxy evolution. Therefore, this thesis covers various topics including black hole mass calculations, the black hole mass-stellar velocity dispersion relation, the nature of AGN emission in galaxy clusters and field galaxies, a detailed investigation of X-ray and optical galaxy overdensity phenomenon, and the dynamical processes in pre-merging galaxy clusters.

Published
2022

37. A well-established harmony in chaos

Author

Caglar, T., Brandl, B.R., Burtscher, L.H., Brinchmann, J., Snellen, I.A.G., Werf, P.P. van der, Kaastra, J.S., Weeren, R.J. van, Morganti, R., Davies, R.I., and Leiden University

Subjects
Active galactic nuclei, Galaxy Clusters, Galaxy Evolution, Bulge, AGN, Galaxies
Abstract

The origin and evolution of galaxies are closely linked to many different physical phenomena. Among them, the most important one is the environment they reside in. Isolated and cluster member galaxies indeed are affected by different forces which affect their evolution. The main concern of this thesis is to understand such forces and how they are related to galaxy evolution. Therefore, this thesis covers various topics including black hole mass calculations, the black hole mass-stellar velocity dispersion relation, the nature of AGN emission in galaxy clusters and field galaxies, a detailed investigation of X-ray and optical galaxy overdensity phenomenon, and the dynamical processes in pre-merging galaxy clusters.

Published
2022

38. Merging galaxy clusters

Author

Di Gennaro, G., Röttgering, H.J.A., Weeren, R.J. van, Hoekstra, H., Kaastra, J.S., Schaye, J., Kale, R., Markevitch, M.L., Ryu, D., Venturi, T., and Leiden University

Subjects
Non-thermal radiation, Astrophysics::High Energy Astrophysical Phenomena, Particle acceleration, Magnetism, Galaxy clusters, Astrophysics::Cosmology and Extragalactic Astrophysics, Large-scale structures, Intracluster medium (ICM)
Abstract

In this thesis, I studied the origin and evolution of the non-thermal radiation in merging galaxy clusters. Cluster mergers are the among the most energetic events in the Universe. Part of this energy is released in turbulence and shock waves which can (re-)accelerate cosmic rays and amplify magnetic fields in the intra-cluster medium (ICM). The interaction of these results in large-scale synchrotron radiation, which is visible through radio observations. In addition, X-ray observations of the ICM were carried out to investigate the dynamical state of the clusters, and the properties of cluster shocks.

Published
2021

39. Unveiling the nature of giant radio galaxies

Author

Dabhade, P., Röttgering, H.J.A., Bagchi, J., Werf, P.P. van der, Israel, F.P., Barthel, P., Morganti, R., Raychaudhury, S., Saikia, D.J., Weeren, R.J. van, and Leiden University

Subjects
Extragalactic astronomy, Supermassive black holes, Radio Astronomy, Giant radio galaxies
Abstract

The thesis deals with the study of giant radio galaxies (GRGs), which are radio galaxies of megaparsec sizes. Their enormous size and rarity have been investigated in this thesis. The study included searching and consequent finding of the largest samples of GRGs and thereby enabling to study of their properties in detail. Also, the properties were compared to smaller sized radio galaxies to investigate possible differences which could be the factor for their giant sizes.

Published
2021

40. Dancing with the stars

Author

Albert, J.G., Röttgering, H.J.A., Weeren, R.J. van, Langevelde, H.J. van, Keller, C.U, Batenburg, K.J., Koopmans, L.V.E., Smirnov, O., Intema, H.T., Tasse, C., Mevius, M., and Leiden University

Subjects
Direction dependent calibration, Ionospheric calibration, Tomographic inference, Radio interferometry
Abstract

This thesis develops a method for direction dependent calibration of the ionosphere in radio interferometric data. The method uses the physical theory of the propagation of radio waves through a random weakly scattering medium, to construct a Gaussian process prior for differential total electron content. We develop a technique for applying this to real data, and apply the technique to several 8-hour LOFAR HBA observations. We find the method is able to, for the first time, remove the direction dependent effects of the ionosphere using a screen based approach. In the process we discover a direction dependent systematic in the data that places a limit of the efficacy of the method.

Published
2020

41. Cosmic particle acceleration by shocks and turbulence in merging galaxy clusters

Author

Hoang, D.N., Röttgering, H.J.A., Shimwell, T., Weeren, R.J. van, Franx, M., Kaastra, J., Miley, G., Ho, P., Intema, H., Akamatsu, H., Simionescu, A., and Leiden University

Subjects
Large-scale structure of Universe, Astrophysics::High Energy Astrophysical Phenomena, Particle acceleration, Galaxy clusters, Astrophysics::Cosmology and Extragalactic Astrophysics, Non-thermal emission
Abstract

In this thesis, I study the formation of large-scale structure and the physics of particle acceleration at large scales (~Mpc). The object of my study is clusters of galaxies that are in the formation process. Galaxy clusters form through a sequence of mergers of sub-clusters. During the formation of galaxy clusters, shocks and turbulence are generated in the intra-cluster medium (ICM). These shocks and turbulence (re-)accelerate cosmic ray (CR) particles to relativistic speeds. In the presence of magnetic fields, the CR particles emit synchrotron radiation that we can observe with radio telescopes. I also combine radio data with X-ray and optical data to study these clusters. Studies of these merging galaxy clusters help us to understand the physics of particle acceleration at cosmic scales

Published
2019

42. Facets of radio-loud AGN evolution : a LOFAR surveys perspective

Author

Williams, W.L., Rottgering, H.J.A, Weeren, R.J. van, Best, P., Brinchmann, J., Franx, M., Garrett, M., Miley, G., Morganti, R., and Leiden University

Subjects
General Relativity and Quantum Cosmology, Radio continuum, Interferometry, Evolution, Black holes, Astrophysics::High Energy Astrophysical Phenomena, Jets, Astrophysics::Cosmology and Extragalactic Astrophysics, AGN, Galaxies
Abstract

Radio observations provide a unique view of black holes in the Universe. This thesis presents low frequency radio images and uses the radio sources in those images to study the evolution of black holes and galaxies through the age of the Universe.

Published
2015

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