MAGIC and H.E.S.S. detect VHE gamma rays from the blazar OT081 for the first time: a deep multiwavelength study

https://pos.sissa.it/395/815/pdfPublished versio

cancer risk and heterozygosity for the mutations 657del5 and R215W

Das Nijmegen Breakage Syndrom (NBS) gehört zur Gruppe der Chromosomeninstabilitätssyndrome und wird durch typische kraniofaziale Veränderungen, milde bis moderate mentale Retardierung, Immundefizienz, chromosomale Instabilität und ein erhöhtes Risiko für die Entwicklung maligner Erkrankungen, v. a. von B-Zell-Lymphomen charakterisiert. Das Syndrom wird durch hypomorphe Mutationen im NBN-Gen verursacht. Über 90% der NBS-Patienten weisen die Mutation 657del5 auf, die auch als Gründer-Mutation oder slawische Mutation bekannt ist. Die meisten Patienten sind slawischer Herkunft. In anderen ethnischen Gruppen ist das Syndrom sehr selten. Aufgrund vieler Ähnlichkeiten wurde das NBS lange Zeit als eine Variante der Ataxia telangiectasia (AT), einer anderen Krankheit aus der Gruppe der chromosomalen Instabilitätssyndrome, betrachtet. Es ist bekannt, dass nicht nur AT- Homozygote sondern auch Heterozygote ein erhöhtes Risiko für maligne Erkrankungen haben. Anhand dieser Parallelen zwischen beiden Syndromen wurde postuliert, dass auch heterozygote Träger für NBN-Mutationen ein erhöhtes Krebsrisiko haben könnten. Die bisherigen Studien hierzu an Patienten mit verschiedenen malignen Erkrankungen ergaben jedoch widersprüchliche Ergebnisse hinsichtlich der Bedeutung von NBN -Mutationen. Im Rahmen dieser Doktorarbeit wurden Patienten mit Non-Hodgkin-Lymphomen (NHL) und verschiedenen soliden Tumoren auf das Vorliegen der NBN-Mutationen 657del5 und R215W untersucht und mit 1620 Kontrollen verglichen. Für die Gruppe der NHL-Patienten wurde eine statistisch signifikante Erhöhung der Zahl der 657del5-Heterozygoten als auch aller Heterozygoten (657del5 + R215W) festgestellt. Des Weiteren fanden wir ein statistisch erhöhtes Risiko bei 657del5-Heterozygoten für Lymphome des gastrointestinalen Traktes. Darüber hinaus untersuchten wir Tumorproben von zwei NBN-Heterozygoten und fanden keinen Hinweis auf den Verlust des Wildtypallels („loss of heterozygosity“). Die Ergebnisse dieser Arbeit lassen den Rückschluss zu, dass der heterozygote NBN-Status mit einem erhöhten Risiko für die Entwicklung von NHL und v. a. NHL des gastrointestinalen Traktes einhergeht. Angesichts der großen Häufigkeit der 657del5 Mutation (slawische Gründermutation) in Osteuropa kommt diesem Befund eine erhebliche medizinische Bedeutung zu.The Nijmegen Breakage Syndrome (NBS) is a recessive autosomal disorder, belonging to a group of chromosomal instability syndromes and is characterized by microcephaly, mild to moderate mental retardation, immunodeficiency, chromosomal instability and a high incidence of non -Hodgkin lymphoma, especially B-cell lymphoma. The syndrome is caused by hypomorphic mutations in the NBN gene. Over 90% of the NBS-Patients carry the mutation 657del5. The majority of the patients are of Slavic origin. Because of the similarities between NBS and Ataxia teleangiectasia (AT), NBS was considered for a long time to be a variant of AT. It is also well known that not only AT-Patients but also heterozygotes for mutations in the ATM-gene have a high risk of developing malignancies. Based on these facts and on familial data, it has been suggested that individuals, heterozygote for NBN-Mutations also have a high risk of developing malignancies. Several studies have been undertaken but the results are contradicting. Within the bounds of this doctoral thesis blood samples from patients with non-Hodgkin lymphoma (NHL) and different cancers were screened for the NBN mutations 657del5 and R215W and compared with 1620 controls. The number of 657del5-heterozygotes as well as the total number of heterozygotes (657del5 +R215W) in the in the HNL group was significantly higher. Also the number of 657del5 heterozygotes among patients with lymphoma of the gastrointestinal tract was significantly higher. Furthermore we analyzed tumor material from two heterozygote patients and could not detect loss of heterozygosity. These findings imply that NBN heterozygosity may contribute significantly to the incidence of NHL, especially of the gastrointestinal tract within the Slavic population

Protons Spectrum from MAGIC Telescopes data

Imaging Atmospheric Cherenkov telescopes (IACTs) are designed to detect cosmic gamma rays. As a by-product, IACTs detect Cherenkov flashes generated by millions of hadronic air showers every night. We present the proton energy spectrum from several hundred GeV to several hundred TeV, retrieved from the hadron induced showers detected by the MAGIC telescopes. The protons are discriminated from He and other heavy nuclei by means of using machine learning classification. The energy estimation is based on a specially developed deep neural network regressor. In the last decade, Deep Learning methods gained much interest in the scientific community for their ability to extract complex relations in data and process large datasets in a short time. The proton energy spectrum obtained in this work is compared to the spectra obtained by dedicated cosmic ray experiments.ISSN:1824-803

Very high energy gamma-ray observation of the peculiar transient event Swift J1644+57 with the MAGIC telescopes and AGILE

Context. On March 28, 2011, the BAT instrument on board the Swift satellite detected a new transient event that in the very beginning was classified as a gamma ray burst (GRB). However, the unusual X-ray flaring activity observed from a few hours up to days after the onset of the event made a different nature seem to be more likely. The long-lasting activity in the X-ray band, followed by a delayed brightening of the source in infrared and radio activity, suggested that it is better interpreted as a tidal disruption event that triggered a dormant black hole in the nucleus of the host galaxy and generated an outflowing jet of relativistic matter. Aims. Detecting a very high energy emission component from such a peculiar object would be enable us to constrain the dynamic of the emission processes and the jet model by providing information on the Doppler factor of the relativistic ejecta. Methods. The MAGIC telescopes observed the peculiar source Swift J1644+57 during the flaring phase, searching for gamma-ray emission at very-high energy (VHE, E > 100 GeV), starting observations nearly 2.5 days after the trigger time. MAGIC collected a total of 28 h of data during 12 nights. The source was observed in wobble mode during dark time at a mean zenith angle of 35 degrees. Data were reduced using a new image-cleaning algorithm, the so-called sum-cleaning, which guarantees a better noise suppression and a lower energy threshold than the standard analysis procedure. Results. No clear evidence for emission above the energy threshold of 100 GeV was found. MAGIC observations permit one to constrain the emission from the source down to 100 GeV, which favors models that explain the observed lower energy variable emission. Data analysis of simultaneous observations from AGILE, Fermi and VERITAS also provide negative detection, which additionally constrain the self-Compton emission component

The blazar TXS 0506+056 associated with a high-energy neutrino: insights into extragalactic jets and cosmic ray acceleration

International audienceA neutrino with energy ∼290 TeV, IceCube-170922A, was detected in coincidence with the BL Lac object TXS 0506+056 during enhanced gamma-ray activity, with chance coincidence being rejected at ∼3σ level. We monitored the object in the very-high-energy (VHE) band with the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes for ∼41 hr from 1.3 to 40.4 days after the neutrino detection. Day-timescale variability is clearly resolved. We interpret the quasi-simultaneous neutrino and broadband electromagnetic observations with a novel one-zone lepto-hadronic model, based on interactions of electrons and protons co-accelerated in the jet with external photons originating from a slow-moving plasma sheath surrounding the faster jet spine. We can reproduce the multiwavelength spectra of TXS 0506+056 with neutrino rate and energy compatible with IceCube-170922A, and with plausible values for the jet power of . The steep spectrum observed by MAGIC is concordant with internal γγ absorption above ∼100 GeV entailed by photohadronic production of a ∼290 TeV neutrino, corroborating a genuine connection between the multi-messenger signals. In contrast to previous predictions of predominantly hadronic emission from neutrino sources, the gamma-rays can be mostly ascribed to inverse Compton upscattering of external photons by accelerated electrons. The X-ray and VHE bands provide crucial constraints on the emission from both accelerated electrons and protons. We infer that the maximum energy of protons in the jet comoving frame can be in the range ∼1014 – 1018 eV

MAGIC detection of short-term variability of the high-peaked BL Lac object 1ES 0806+524

ISSN:0035-8711ISSN:1365-2966ISSN:1365-871

Intensity interferometry with the MAGIC telescopes

Due to their large mirror size, fast response to single photons, sensitivity and telescope baselines in the order of 100 m, Imaging Atmospheric Cherenkov Telescopes are ideally suited to perform intensity interferometry observations. In 2019 a test readout setup was installed in the two 17-m diameter MAGIC telescopes to allow performing interferometry measurements with them. The first on-sky measurements were able to detect correlated intensity fluctuations consistent with the stellar diameters of three different stars: Adhara (n CMa), Benetnasch ([ UMa) and Mirzam (V CMa). After the upgrade of the setup in 2021, MAGIC is now equipped with a high-duty-cycle intensity interferometer, already in operation. A technical description of the interferometer and first performance results obtained by measuring several known stellar diameter are presented

Extreme blazars under the eyes of MAGIC

Extreme high-frequency-peaked BL Lac objects (EHBLs) are the most energetic persistent sources in the universe. This contribution reports on long-term observing campaigns of tens of EHBLs that have been organized by the MAGIC collaboration to enlarge their population at VHE and understand the origin of their extreme properties. EHBLs are characterized by a spectral energy distribution (SED) featuring a synchrotron peak energy above 1 keV. Several EHBLs display a hard spectral index at very high energies (VHE; E > 100 GeV), suggesting a gamma-ray SED component peaking significantly above 1 TeV. Such extreme properties are challenging current standard emission and acceleration mechanisms. Recent studies have also unveiled intriguing disparities in the temporal characteristics of EHBLs. Some sources seem to display a persistent EHBL behaviour, while others belong to the EHBL family only temporarily. Here, we present recent results of the first hard-TeV EHBL catalog. The MAGIC observations are accompanied by an extensive multiwavelength coverage to obtain an optimal determination of the SED. This allow us to investigate leptonic and hadronic scenarios for the emission. We also present the recent detection of the EHBL RX J0812.0+0237 in the VHE band by MAGIC. Finally, we discuss a broad multiwavelength campaign on the BL Lac type object 1ES 2344+514, which showed intermittent EHBL characteristics in August 2016