15159726
First results from the lick AGN monitoring project: The mass of the black hole in ARP 151
We have recently completed a 64 night spectroscopic monitoring campaign at the Lick Observatory 3 m Shane telescope with the aim of measuring the masses of the black holes in 13 nearby (z < 0.05) Seyfert 1 galaxies with expected masses in the range ~106-107 M☉. We present here the first results from this project—the mass of the central black hole in Arp 151. Strong variability throughout the campaign led to an exceptionally clean Hβ lag measurement in this object of 4.25−0.66+0.68 days in the observed frame. Coupled with the width of the Hβ emission line in the variable spectrum, we determine a black hole mass of (7.1 ± 1.2) × 106 M☉, assuming the Onken et al. normalization for reverberation-based virial masses. We also find velocity-resolved lag information within the Hβ emission line which clearly shows infalling gas in the Hβ-emitting region. Further detailed analysis may lead to a full model of the geometry and kinematics of broad line region gas around the central black hole in Arp 151.
15737210
CORONAL LINES AND DUST FORMATION IN SN 2005ip: NOT THE BRIGHTEST, BUT THE HOTTEST TYPE IIn SUPERNOVA
We present optical photometry and spectroscopy of SN 2005ip for the first 3 yr after discovery, showing an underlying Type II-L supernova (SN) interacting with a steady wind to yield an unusual Type IIn spectrum. For the first ~160 days, it had a fast linear decline from a modest peak absolute magnitude of about –17.4 (unfiltered), followed by a plateau at roughly –14.8 for more than 2 yr. Initially having a normal broad-lined spectrum superposed with sparse narrow lines from the photoionized circumstellar medium (CSM), it quickly developed signs of strong CSM interaction with a spectrum similar to that of SN 1988Z. As the underlying SN II-L faded, SN 2005ip exhibited a rich high-ionization spectrum with a dense forest of narrow coronal lines, unprecedented among SNe but reminiscent of some active galactic nuclei. The line-profile evolution of SN 2005ip confirms that dust formation caused its recently reported infrared excess, but these lines reveal that it is the first SN to show clear evidence for dust in both the fast SN ejecta and the slower postshock gas. SN 2005ip's complex spectrum confirms the origin of the strange blue continuum in SN 2006jc, which also had postshock dust formation. We suggest that SN 2005ip's late-time plateau and coronal spectrum result from rejuvenated CSM interaction between a sustained fast shock and a clumpy stellar wind, where X-rays escape through the optically thin interclump regions to heat the preshock CSM to coronal temperatures.
16104319
The Lick AGN Monitoring Project: Broad-line Region Radii and Black Hole Masses from Reverberation Mapping of Hβ
We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3-m Shane telescope with the aim of measuring the masses of the black holes in 12 nearby (z < 0: 05) Seyfert 1 galaxies with expected masses in the range � 10 6 -10 7 Mand also the well-studied nearby active galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including NGC 5548) showed optical variability of sufficient strength during the monitoring campaign to all ow for a time lag to be measured between the continuum fluctuations and the response to these fluctuation s in the broad Hemission. We present here the light curves for all the objects in this sample and the subseq uent Htime lags for the nine objects where these measurements were possible. The Hlag time is directly related to the size of the broad-line reg ion in AGNs, and by combining the Hlag time with the measured width of the Hemission line in the variable part of the spectrum, we determine the virial mass of the central sup ermassive black hole in these nine AGNs. The absolute calibration of the black hole masses is based on the normalization derived by Onken et al., which brings the masses determined by reverberation mapping into agreement with the local MBH -�? relationship for quiescent galaxies. We also examine the time lag response as a function of velocity across the Hline profile for six of the AGNs. The analysis of four leads to rather ambiguous results with relatively flat time lags as a function of velocity. However, SBS 1116+583A exhibits a symmetric time lag response around the line center reminiscent of simple models for circularly orbiting broad -line region (BLR) clouds, and Arp 151 shows an asymmetric profile that is most easily explained by a simple g ravitational infall model. Further investigation will be necessary to fully understand the constraints place d on physical models of the BLR by the velocity- resolved response in these objects. Subject headings:galaxies: active - galaxies: nuclei - galaxies: Seyfert
118664939
Nearby supernova rates from the Lick Observatory Supernova Search – III. The rate–size relation, and the rates as a function of galaxy Hubble type and colour
This is the third paper of a series in which we present new measurements of the observed rates of supernovae (SNe) in the local Universe, determined from the Lick Observatory Supernova Search (LOSS). We have considered a sample of ∼1000 SNe and used an optimal subsample of 726 SNe (274 SNe Ia, 116 SNe Ibc and 324 SNe II) to determine our rates. We study the trend of the rates as a function of a few quantities available for our galaxy sample, such as luminosity in the B and K bands, stellar mass and morphological class. We discuss different choices (SN samples, input SN luminosity functions, inclination correction factors) and their effect on the rates and their uncertainties. A comparison between our SN rates and the published measurements shows that they are consistent with each other to within the uncertainties when the rate calculations are done in the same manner. Nevertheless, our data demonstrate that the rates cannot be adequately described by a single parameter using either galaxy Hubble types or B ― K colours. A secondary parameter in galaxy 'size', expressed by luminosity or stellar mass, is needed to adequately describe the rates in the rate-size relation: the galaxies of smaller sizes have higher SN rates per unit mass or per unit luminosity. The trends of the SN rates in galaxies of different Hubble types and colours are discussed. We examine possible causes for the rate-size relation. Physically, such a relation for the core-collapse SNe is probably linked to the correlation between the specific star-formation rate and the galaxy sizes, but it is not clear whether the same link can be established for SNe Ia. We discuss the two-component ('tardy' and 'prompt') model for SN Ia rates, and find that the SN Ia rates in young stellar populations might have a strong correlation with the core-collapse SN rates. We derive volumetric rates for the different SN types [e.g. for SNe Ia, a rate of (0.301 ± 0.062) x 10 ―4 SN Mpc ―3 yr ―1 at redshift 0] and compare them to the measurements at different redshifts. Finally, we estimate the SN rate for the Milky Way Galaxy to be 2.84 ± 0.60 SNe per century (with a systematic uncertainty of a factor of ∼2), consistent with published SN rates based on several different techniques.
118550346
Exotic collective excitations at high spin: Triaxial rotation and octupole condensation
In this thesis work, two topics, triaxiality and reflection asymmetry, have been discussed. Band structures in $^{163}$Tm were studied in a "thin" target experiment as well as in a DSAM lifetime measurement. Two new excited bands were shown to be characterized by a deformation larger than that of the yrast sequence. These structures have been interpreted as Triaxial Strongly Deformed bands associated with particle-hole excitations, rather than with wobbling. Moreover, the Tilted-Axis Cranking calculations provide a natural explanation for the presence of wobbling bands in the Lu isotopes and their absence in the neighboring Tm, Hf and Ta nuclei. A series of so-called "unsafe" Coulomb excitation experiments as well as one-neutron transfer measurements was carried out to investigate the role of octupole correlations in the $^{238,240,242}$Pu isotopes. Some striking differences exist between the level scheme and deexcitation patterns seen in $^{240}$Pu, and to a lesser extent in $^{238}$Pu, and those observed in $^{242}$Pu and in many other actinide nuclei such as $^{232}$Th and $^{238}$U, for example. The differences can be linked to the strength of octupole correlations, which are strongest in $^{240}$Pu. Further, all the data find a natural explanation within the recently proposed theoretical framework of octupole condensation.
55046954
Berkeley Supernova Ia Program - I. Observations, data reduction and spectroscopic sample of 582 low-redshift Type Ia supernovae
In this first paper in a series, we present 1298 low-redshift (z ≲ 0.2) optical spectra of 582 Type Ia supernovae (SNe Ia) observed from 1989 to 2008 as part of the Berkeley Supernova Ia Program (BSNIP). 584 spectra of 199 SNe Ia have well-calibrated light curves with measured distance moduli, and many of the spectra have been corrected for host-galaxy contamination. Most of the data were obtained using the Kast double spectrograph mounted on the Shane 3 m telescope at Lick Observatory and have a typical wavelength range of 3300–10 400 A, roughly twice as wide as spectra from most previously published data sets. We present our observing and reduction procedures, and we describe the resulting SN Database, which will be an online, public, searchable data base containing all of our fully reduced spectra and companion photometry. In addition, we discuss our spectral classification scheme (using the SuperNova IDentification code, snid; Blondin & Tonry), utilizing our newly constructed set of snid spectral templates. These templates allow us to accurately classify our entire data set, and by doing so we are able to reclassify a handful of objects as bona fide SNe Ia and a few other objects as members of some of the peculiar SN Ia subtypes. In fact, our data set includes spectra of nearly 90 spectroscopically peculiar SNe Ia. We also present spectroscopic host-galaxy redshifts of some SNe Ia where these values were previously unknown. The sheer size of the BSNIP data set and the consistency of our observation and reduction methods make this sample unique among all other published SN Ia data sets and complementary in many ways to the large, low-redshift SN Ia spectra presented by Matheson et al. and Blondin et al. In other BSNIP papers in this series, we use these data to examine the relationships between spectroscopic characteristics and various observables such as photometric and host-galaxy properties.
123633000
The Higgs Boson Mass in MSM and the New Data
In this paper we study the implications of the top quark mass measurement at CDF for the Higgs boson mass . We find that the present data are most likely in favor of heavy Higgs boson, for , but no realistic constraints on could be derived until the measurement of reaches high precision.
64266626
Top quark pair production via $e^{+}e^{-}$ collision in the littlest Higgs model with T-parity at the ILC
In the framework of the littlest Higgs model with T parity, we studied the contributions of the new particles to the top-quark pair production via e{sup +}e{sup -} collision at the International Linear Collider. We calculated the top-quark pair production cross section and found this process can generate significantly relative correction. The result may be a sensitive probe of the littlest Higgs model with T parity.
123068508
Near-infrared observations of candidate extrinsic S stars
Photometric observations in the near infrared for 161 S stars, including 18 Tc-rich (intrinsic) stars, 19 Tc-deficient (extrinsic) ones and 124 candidates for Tc-deficient S stars, are presented in this paper. Based on some further investigations into the infrared properties of both Tc-rich and Tc-deficient S stars, 104 candidates are identified as very likely Tc-deficient S stars. The large number of infrared-selected Tc-deficient S stars provides a convenient way to study the physical properties and the evolutionary status of this species of S stars.
119232006
Testing the Littlest Higgs Model with T-parity in Bottom Quark Pair Production at High Energy Photon Colliders
We have calculated the cross section of the process e(+)e(-)->gamma gamma -> bb in the littlest Higgs model with T parity (LHT). We find that, for the favorable parameters, the total cross section sigma(e(+)e(-)->gamma gamma -> bb) is sensitive to the breaking scale f, mixing parameter x(L), the masses of the mirror quarks m(Hi), and the relative correction of the LHT model is a few percent to dozens of percent. The cross section is significantly larger than the corresponding results in the standard model and in the other typical new physics models. Therefore the prediction in the LHT model is quite different from the predictions in other new physics models and such a process is really interesting in searching for the signs of the LHT model.
123423629
Implications of the top quark mass measurement for the SM Higgs boson mass MH
Motivated by the recent determination of the top quark mass by the CDF Collaboration Mt=174+or-10-12+13 GeV, we study,the implications of the top quark mass measurement for the standard model Higgs boson mass MH based on the phenomenological analysis of the radiative correction Delta r at two-loop order. We find that: (a) the central value of MH is very sensitive to the variation of Mt; (b) the present data are in favour of the heavy Higgs boson, MH=340-270+770 GeV for Mt=174 GeV, but no reliable constraints on MH could be derived until the measurement of Mt reaches high precision.