Radio observations of peculiar galaxies

With the 1000-foot radiotelescope of the Arecibo Ionospheric Observatory we have observed the positions of 69 peculiar galaxies classified by Arp (1966). Several radio sources were detected, but they could be chance coincidences. Radio maps of the radio sources are given.Asociación Argentina de Astronomí

Radio observations of peculiar galaxies

With the 1000-foot radiotelescope of the Arecibo Ionospheric Observatory we have observed the positions of 69 peculiar galaxies classified by Arp (1966). Several radio sources were detected, but they could be chance coincidences. Radio maps of the radio sources are given.Asociación Argentina de Astronomí

Radio observations of peculiar galaxies

With the 1000-foot radiotelescope of the Arecibo Ionospheric Observatory we have observed the positions of 69 peculiar galaxies classified by Arp (1966). Several radio sources were detected, but they could be chance coincidences. Radio maps of the radio sources are given.Asociación Argentina de Astronomí

Observaciones en la línea de 21 cm del remanente de supernova G 261.9 + 5.5

Con el radiotelescopio de 30 m del I.A.R. se efectuó un relevamiento del hidrógeno neutro asociado con el remanente de supernova G 261.9 + 5.5. Se analizan las estructuras probablemente asociadas con el mismo, a velocidades intermedias y altas.Asociación Argentina de Astronomí

Aleyrodes lonicerae Walker una nuova avversit\ue0 per Cyclamen persicum Miller

Viene segnalato il ritrovamento in Lombardia di Aleyrodes lonicerae Walker su ciclamino spontaneo e coltivato. Questo aleirodide che, citato in bibliografia su numerose specie vegetali, non era ancora stato segnalato su primulacee, si va ad aggiungere alle molte avversit\ue0 del ciclamino coltivato.The findings in Lombardy of Aleyrodes lonicerae is recorded on cultivated and wild Cyclamen. This whitefly which has been cited on various vegetal species but never on Primulaceae, is added to the others Cyclamen pests

Planck intermediate results. VIII. Filaments between interacting clusters

About half of the baryons of the Universe are expected to be in the form of filaments of hot and low density intergalactic medium. Most of these baryons remain undetected even by the most advanced X-ray observatories which are limited in sensitivity to the diffuse low density medium. The Planck satellite has provided hundreds of detections of the hot gas in clusters of galaxies via the thermal Sunyaev-Zel'dovich (tSZ) effect and is an ideal instrument for studying extended low density media through the tSZ effect. In this paper we use the Planck data to search for signatures of a fraction of these missing baryons between pairs of galaxy clusters. Cluster pairs are good candidates for searching for the hotter and denser phase of the intergalactic medium (which is more easily observed through the SZ effect). Using an X-ray catalogue of clusters and the Planck data, we select physical pairs of clusters as candidates. Using the Planck data we construct a local map of the tSZ effect centered on each pair of galaxy clusters. ROSAT data is used to construct X-ray maps of these pairs. After having modelled and subtracted the tSZ effect and X-ray emission for each cluster in the pair we study the residuals on both the SZ and X-ray maps. For the merging cluster pair A399-A401 we observe a significant tSZ effect signal in the intercluster region beyond the virial radii of the clusters. A joint X-ray SZ analysis allows us to constrain the temperature and density of this intercluster medium. We obtain a temperature of kT = 7.1 +- 0.9, keV (consistent with previous estimates) and a baryon density of (3.7 +- 0.2)x10^-4, cm^-3. The Planck satellite mission has provided the first SZ detection of the hot and diffuse intercluster gas.Comment: Accepted by A&

Planck 2015 results. XXVII. The Second Planck Catalogue of Sunyaev-Zeldovich Sources

We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest all-sky catalogue of galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data-sets, and is the first SZ-selected cluster survey containing > $10^3$ confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the Y5R500 estimates are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires. the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical and X-ray data-sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under- luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples

Planck early results V : The Low Frequency Instrument data processing

Peer reviewe

Planck intermediate results XIII : Constraints on peculiar velocities

Peer reviewe

Planck early results III : First assessment of the Low Frequency Instrument in-flight performance

Peer reviewe