The flat spectrum radio quasar (FSRQ) PKS 1510-089 (z=0.361) is known for its complex multiwavelength behavior. It has been monitored regularly at very high energy (VHE, \(E>100\,\)GeV) gamma-rays ...with H.E.S.S. since its discovery in 2009 in order to study the unknown behavior of FSRQs in quiescence at VHE, as well as the flux evolution around flaring events. Given the expected strong cooling of electrons and the absorption of VHE emission within the broad-line region, a detection of PKS 1510-089 at VHE in a quiescent state would be an important result, implying an acceleration and emission region on scales beyond the broad-line region. The H.E.S.S. monitoring has been intensified since 2015 and is complemented by monitoring at high energy (\(E>100\,\)MeV) gamma-rays with Fermi, at X-rays with Swift-XRT, and at optical frequencies with ATOM. The dense lightcurves allow for the first time detailed comparison studies between these energy bands. The source has been active in several frequency bands for a large fraction of the observation time frames. Yet, we do not find obvious correlations between the VHE and the other bands over the observed time frame indicating a non-trivial interplay of the acceleration, cooling and radiative processes. It also implies a rich variety in flaring behavior, which makes this source difficult to interpret within a unique theoretical framework.
The blazar PKS 1510-089 was the first of the flat spectrum radio quasar type, which had been detected simultaneously by a ground based Cherenkov telescope (H.E.S.S.) and the LAT instrument on board ...the Fermi satellite. Given the strong broad line region emission defining this blazar class, and the resulting high optical depth for VHE (\(E>100\,\)GeV) \(\gamma\)-rays, it was surprising to detect VHE emission from such an object. In May 2015, PKS 1510-089 exhibited high states throughout the electromagnetic spectrum. Target of Opportunity observations with the H.E.S.S. experiment revealed strong and unprecedented variability of this source. Comparison with the lightcurves obtained with the \textit{Fermi}-LAT in HE \(\gamma\)-rays (\(100\,\)MeV\(<E<100\,\)GeV) and ATOM in the optical band shows a complex relationship between these energy bands. This points to a complex structure of the emission region, since the one-zone model has difficulties to reproduce the source behavior even when taking into account absorption by ambient soft photon fields. It will be shown that the presented results have important consequences for the explanation of FSRQ spectra and lightcurves, since the emission region cannot be located deep inside the broad line region as is typically assumed. Additionally, acceleration and cooling processes must be strongly time-dependent in order to account for the observed variability patterns.
With the installation of a new 28-m diameter imaging atmospheric Cherenkov telescope in the middle of the array, the H.E.S.S. instrument has entered since 2012 into its Phase II. The fifth large-size ...telescope is particularly important to lower the threshold energy of the array, and is thus a unique instrument to observe low-frequency-peaked blazars, such as flat-spectrum radio-quasars (FSRQs), which remain rare in the very-high- energy (VHE; E \(>\) 100 GeV) \(\gamma\)-ray domain. In this contribution, we report on the discovery with the H.E.S.S. telescopes of VHE \(\gamma\)-ray emission from the FSRQ PKS 0736+017 (z=0.189). H.E.S.S. observations were triggered as a target-of-opportunity in February 2015 following the detection of \(\gamma\)-ray flaring activity in the MeV-GeV energy-band with Fermi-LAT. Significant VHE emission is detected with H.E.S.S. only during one of the nights of the observing campaign, showing at least night-by-night variability in the VHE regime. We discuss the location of the \(\gamma\)-ray emitting region within the relativistic jet, using opacity and variability constraints.
In 311 patients (269 men and 42 woman, 20 to 65 years old) without transmural myocardial infarction the results of exercise tests in supine position were compared with the results of coronary ...angiography. 1. Patients having ischemic ST-segment depression (greater than or equal to 0.1 mV) and angina pectoris during exercise (n = 108) showed a greater than or equal to 50% stenosis of at least one vessel in 86.1%. In men the number of a greater than or equal to 50% stenosis was significantly higher than in women (91.3 vs. 56.2%). In patients without digitalis agreement with coronary angiographic findings is higher than in patients with digitalis (92.7 vs. 79.2%). After excluding women, patients under digitalis and those with an intramural myocardial infarction, agreement was 96.8%. 2. In patients having ischemic ST-segment depression agreement was 30% and in those with angina pectoris 36.8%. 3. In patients having neither ischemic ST-segment depression nor angina pectoris during exercise up to a heart rate of 80% of the age-dependent heart rate limit a coronary angiogram without a greater than or equal to 50% stenosis was found in 87.6%. After excluding patients with an intramural myocardial infarction, women and patients under digitalis, agreement increased to 97.9%. 4. In patients having both ischemic ST-segment depression and angina pectoris during exercise a 2- or 3-vessel disease was more often found than in patients having either ischemic ST-segment depression or angina pectoris, or in those having neither ischemic ST-segment depression nor angina pectoris respectively (57.5% vs. 16.6, 8.9 and 1.9%). 5. The number of positive coronary angiograms, especially of 2- and 3-vessel disease, increases with the degree of an ischemic ST-segment depression and the reduction of exercise tolerance.
The correlation between the three ischemia indicators angina pectoris (AP), ST-segment depression (ST) and excessive pulmonary wedge pressure rise (PCP) during exercise, and the coronary angiographic ...findings, were analysed in 293 patients without previous transmural myocardial infarction. This patient material consisted of 253 men and 40 women between the age of 20 and 65 years, the mean age being 48. The exercise tests were performed on a bicycle ergometer in supine position and in relatively steady state conditions. Pulmonary wedge pressure was measured by means of a Swan-Ganz floating catheter. The essential findings were: 1. If all three ischemia indicators were positive, the incidence of a positive angiographic finding i.e. a greater than or equal to 50% stenoses in at least one main coronary artery was 96.3%. 2. If only the two classic ischemia indicators were evaluated and positive, the incidence of a positive angiographic finding was only 86.1% (24). This difference is mainly due to false positive results of AP and ST in women. 3. If all three ischemia indicators were negative, the incidence of a negative angiographic finding was 89.2%. 4. If only the two classic ischemia indicators were evaluated and negative the incidence of a negative angiographic finding was as high (87,6% 24). This lack of difference is due to the fact that patients with a previous intramural infarcion can be free not only of AP and ST but also of PCP during exercise. 5. The combination of AP and PCP, or ST and PCP, is equally reliable in predicting coronary morphology as the classic combination of AP and ST. It follows that PCP measurement is recommended, if one of the classic ischemia indicators cannot be properly evaluated.
PDF
