VERITAS and Fermi-LAT Observations of TeV Gamma-Ray Sources Discovered by HAWC in the 2HWC Catalog
(2018)
The High Altitude Water Cherenkov (HAWC) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100 GeV) gamma-ray sources based on 507 days of observation. Among these, 19 sources are not associated with previously known teraelectronvolt (TeV) gamma-ray sources. We have studied 14 of these sources without known counterparts with VERITAS and Fermi-LAT. VERITAS detected weak gamma-ray emission in the 1 TeV-30 TeV band in the region of DA 495, a pulsar wind nebula coinciding with 2HWC J1953+294, confirming the discovery of the source by HAWC. We did not find any counterpart for the selected 14 new HAWC sources from our analysis of Fermi-LAT data for energies higher than 10 GeV. During the search, we detected gigaelectronvolt (GeV) gamma-ray emission coincident with a known TeV pulsar wind nebula, SNR G54.1+0.3 (VER J1930+188), and a 2HWC source, 2HWC J1930+188. The fluxes for isolated, steady sources in the 2HWC catalog are generally in good agreement with those measured by imaging atmospheric Cherenkov telescopes. However, the VERITAS fluxes for SNR G54.1+0.3, DA 495, and TeV J2032+4130 are lower than those measured by HAWC, and several new HAWC sources are not detected by VERITAS. This is likely due to a change in spectral shape, source extension, or the influence of diffuse emission in the source region.
Prólogo
(2017)
Vorwort
(2017)
This paper focuses on the religious background of lawgiving and its mythical models in books I-IV of the Laws. This latest of Plato's Works deals with the main tasks of a legislator in the ideal political community. In this dialogue, the lawgiver (nomothetes) is the heir of a long Greek tradition with mythical and historical forerunners (Solon, Lycurgus, Epimenides, etc.) who had a special relation with the divinity. Perhaps the best example of this kind of divine lawgiver is Minos, who was able of knowing the Gods' will and received from them the holy laws. In that aspect, Plato depends on the legendary nomothetai from myth and dwells heavily in oracular procedures as a way of communication with divinity and acquisition of decrees or confirmation of laws. If our view is correct, the model for the best possible constitution comes from Divine Wisdom (i.e. Philosophy) through oracular mediation from their mythical origins in Crete and Egypt. The medium between Gods and Men and its mantic practices - as the holy men (theioi andres) from myth and archaic Greek politics - seems a key figure for a better understanding of Plato's most complex dialogue.