Discovery of Very High Energy Gamma Rays from 1ES 1440+122

The BL Lacertae object 1ES 1440+122 was observed in the energy range from 85 GeV to 30 TeV by the VERITAS array of imaging atmospheric Cherenkov telescopes. The observations, taken between 2008 May and 2010 June and totalling 53 hours, resulted in the discovery of $\gamma$-ray emission from the blazar, which has a redshift $z$=0.163. 1ES 1440+122 is detected at a statistical significance of 5.5 standard deviations above the background with an integral flux of (2.8$\pm0.7_{\mathrm{stat}}\pm0.8_{\mathrm{sys}}$) $\times$ 10$^{-12}$ cm$^{-2}$ s$^{-1}$ (1.2\% of the Crab Nebula's flux) above 200 GeV. The measured spectrum is described well by a power law from 0.2 TeV to 1.3 TeV with a photon index of 3.1 $\pm$ 0.4$_{\mathrm{stat}}$ $\pm$ 0.2$_{\mathrm{sys}}$. Quasi-simultaneous multi-wavelength data from the Fermi Large Area Telescope (0.3--300 GeV) and the Swift X-ray Telescope (0.2--10 keV) are additionally used to model the properties of the emission region. A synchrotron self-Compton model produces a good representation of the multi-wavelength data. Adding an external-Compton or a hadronic component also adequately describes the data.Comment: 8 pages, 4 figures. Accepted for publication in MNRA

Reactivity of CuI and CuBr toward Dialkyl Sulfides RSR: From Discrete Molecular Cu 4

The 1D coordination polymer (CP) [(Me2S)(3){Cu-2(mu-I)(2)}](n) (1) is formed when CuI reacts with SMe2 in n-heptane, whereas in acetonitrile (MeCN), the reaction forms exclusively the 2D CP [(Me2S)(3){Cu-4(mu-I)4}](n) (2) containing flower-basket Cu4I4 units. The reaction product of CuI with MeSEt is also solvent-dependent, where the 1D polymer [(MeSEt)(2){Cu-4(mu(3)-I)(2)(mu(2)-I)(2)}(MeCN)(2)](n) (3) containing stepped-cubane Cu4I4 units is isolated in MeCN. In contrast, the reaction in n-heptane affords the 1D CP [(MeSEt)(3){Cu-4(mu(3)-I)4}](n) (4) containing closed-cubane Cu4I4 clusters. The reaction of MeSPr with CuI provides the structurally related 1D CP [(MeSPr)(3){Cu-4(mu(3)-I)4}](n) (5), for which the X-ray structure has been determined at 115, 155, 195, 235, and 275 K, addressing the evolution of the metric parameters. Similarly to 4 and the previously reported CP [(Et2S)(3){Cu-4(mu(3)-I)4}](n) (Inorg. Chem. 2010, 49, 5834), the 1D chain is built upon closed cubanes Cu-4(mu(3)-I)4 as secondary building units (SBUs) interconnected via mu-MeSPr ligands. The 0D tetranuclear clusters [(L)4{Cu-4(mu(3)-I)4}] [L = EtSPr (6), Pr2S (7)] respectively result from the reaction of CuI with EtSPr and n-Pr2S. With i-Pr2S, the octanuclear cluster [(i-Pr2S)(6){Cu-8(mu(3)-I)(3)}(mu(4)-I)(2)}] (8) is formed. An X-ray study has also been performed at five different temperatures for the 2D polymer [(Cu3Br3)(MeSEt)(3)](n) (9) formed from the reaction between CuBr and MeSEt in heptane. The unprecedented framework of 9 consists of layers with alternating Cu(mu(2)-Br)(2)Cu rhomboids, which are connected through two mu-MeSEt ligands to tetranuclear open-cubane Cu4Br4 SBUs. MeSPr forms with CuBr in heptane the 1D CP [(Cu3Br3)(MeSPr)(3)](n) (10), which is converted to a 2D metalorganic framework [(Cu5Br5)(mu(2)-MeSPr)(3)](n) (11) incorporating pentanuclear [(Cu-5(mu(4)-Br)(mu(2)-Br)] SBUs when recrystallized in MeCN. The thermal stability and photophysical properties of these materials are also reported

Multiwavelength study of quiescent states of mrk 421 with unprecedented hard x-ray coverage provided bynustarin 2013

We present coordinated multiwavelength observations of the bright, nearby BL Lacertae object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations and instruments, providing data from radio to very high energy. (VHE).-ray bands. NuSTAR yielded previously unattainable sensitivity in the 3-79. keV range, revealing that the spectrum softens when the source is dimmer until the X-ray spectral shape saturates into a steep Gamma approximate to 3 power law, with no evidence for an exponential cutoff or additional hard components up to similar to 80. keV. For the first time, we observed both the synchrotron and the inverse-Compton peaks of the spectral energy distribution (SED) simultaneously shifted to frequencies below the typical quiescent state by an order of magnitude. The fractional variability as a function of photon energy shows a double-bump structure that relates to the two bumps of the broadband SED. In each bump, the variability increases with energy, which, in the framework of the synchrotron self-Compton model, implies that the electrons with higher energies are more variable. The measured multi band variability, the significant X-ray-to-VHE correlation down to some of the lowest fluxes ever observed in both bands, the lack of correlation between optical/UV and X-ray flux, the low degree of polarization and its significant (random) variations, the short estimated electron cooling time, and the significantly longer variability timescale observed in the NuSTAR light curves point toward in situ electron acceleration and suggest that there are multiple compact regions contributing to the broadband emission of Mrk 421 during low-activity states