Physical Sciences and Mathematics | Open Access Articles

Discovery Of The Near-Ir Afterglow And Of The Host Of Grb 030528, A. Rau, J. Greiner, S. Klose, M. Salvato, J. M. Castro Cerón, Dieter H. Hartmann, A. Fruchter, A. Levan, N. R. Tanvir, J. Gorosabel

Publications

The rapid dissemination of an arcmin-sized HETE-2 localization of the long-duration X-ray ﬂash GRB 030528 led to a ground-based multi-observatory follow-up campaign. We report the discovery of the near-IR afterglow, and also describe the detection of the underlying host galaxy in the optical and near-IR bands. The afterglow is classiﬁed as “optically dark” as it was not detected in the optical band. The K-band photometry presented here suggests that the lack of optical detection was simply the result of observational limitations (lack of rapid and deep observations plus high foreground extinction). Simple power law ﬁts to the afterglow in the …

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Discovery Of Co Gas In The Inner Disk Of Tw Hydrae, Terrence W. Rettig, Joe Haywood, Theodore Simon, Sean D. Brittain, Erika Gibb

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We report the detection of rovibrationally excited CO emission from the inner disk of the classical T Tauri star (cTTS) TW Hya. We observe ~6 × 1021 g of CO gas with a rotational temperature of 430 ± 40 K. The linearity of the excitation plot suggests that the CO is optically thin. Atypical for cTTSs, hot CO was not detected, implying that TW Hya has cleared its inner disk region out to a radial distance of ~0.5 AU. We discuss implications for the structure of the disk as it relates to replenishment and planet formation.

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Probing A Grb Progenitor At A Redshift Of Z=2: A Comprehensive Observing Campaign Of The Afterglow Of Grb 030226, S. Klose, J. Greiner, A. Rau, A. A. Henden, Dieter H. Hartmann, A. Zeh, C. Reis, N. Masetti, D. Malesani, E. Guenther

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We report results from a comprehensive follow-up observing campaign of the afterglow of GRB 030226, in-cluding VLTspectroscopy, VLT polarimetry, and Chandra X-ray observations. In addition, we present BOOTES-1 wide-ﬁeld observations at the time of the occurrence of the burst. First observations at ESO started 0.2 days after the event when the gamma ray burst (GRB) afterglow was at a magnitude of R $19 and continued until the afterglow had faded below the detection threshold (R > 26). No underlying host galaxy was found. The optical light curve shows a break around 0.8 days after the burst, which is achromatic within the …

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The Correlation Of Lithium And Beryllium In F And G Cluster Dwarf Stars, Ann Merchant Boesgaard, Eric Armengaud, Constantine P. Deliyannis, Alex Stephens, Jeremy R. King

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Although Li has been extensively observed in main-sequence ﬁeld and cluster stars, there are relatively fewer observations of Be. We have obtained Keck HIRES spectra of 36 late F and early G dwarfs in order to study the Li-Be correlation we found previously in the temperature regime of 5900–6650 K. The sample size for this temperature range with detectable and (usually) depleted Li and Be is now 88, including Li and Be abundances in both cluster and ﬁeld stars. Therefore we can now investigate the inﬂuence of other parameters such as age, temperature, and metallicity on the correlation. The Be …

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Spin Mass Of An Electron Liquid, Zhixin Qian, Giovanni Vignale, D C. Marinescu

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We show that in order to calculate correctly the spin current carried by a quasiparticle in an electron liquid one must use an effective ‘‘spin mass’’ ms that is larger than both the band mass mb, which determines the charge current, and the quasiparticle effective mass m, which determines the heat capacity. We present two independent estimates of the spin mass enhancement, ms=mb, in two- and three-dimensional electron liquids, based on (i) previously calculated values of the Landau parameters and (ii) a recent theory of the dynamical local ﬁeld factor in the spin channel. Both methods yield a signiﬁcant spin …

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The Li Overabundance Of J37: Diﬀusion Or Accretion?, J F. Ashwell, R D. Jeffries, C P. Deliyannis, A Steinhauer, Jeremy R. King

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In September 2002 the discovery of a super Li-rich F-dwarf (J37) in NGC 6633, an iron poor analogue of the better studied Hyades and Praecepe open clusters, was announced. This unique star was thought to be the smoking gun for the action of diﬀusion, models of which predict a narrow ”Li-peak” at approximately the correct temperature. However, with more detailed studies into J37s abundance pattern this star provides ﬁrm evidence for the accretion of planetesimals or other material from the circumstellar environment of new born stars. Thanks to the speciﬁc predictions made about the behaviour of Be abundances, (the most …

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The Near-Infared Survey Of The N49 Region Around The Soft Gamma Repeater Sgr 0526-66, S. Klose, A. A. Henden, U. Geppert, J. Greiner, H. H. Guetter, Dieter H. Hartmann, C. Kouveliotou, C. B. Luginbuhl, B. Stecklum, F. J. Vrba

Publications

We report the results of a deep near-infrared survey with the Very Large Telescope/Infrared Spectrometer and Array Camera of the environment of the supernova remnant N49 in the Large Magellanic Cloud, which contains the soft gamma repeater SGR 0526-66. Two of the four conﬁrmed SGRs are potentially associated with compact stellar clusters. We thus searched for a similar association of SGR 0526-66 and imaged a young stellar cluster at a projected distance of ∼30 pc from the SGR. This constitutes the third cluster–SGR link and lends support to scenarios in which SGR progenitors originate in young dusty clusters. If conﬁrmed, …

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The Upper Limit For Ch4 In The Protostellar Disk Toward Hl Tauri, E L. Gibb, T Rettig, Sean D. Brittain, R Haywood, Theodore Simon, C Kulesa

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We used high-resolution infrared spectra of the heavily embedded T Tauri star HL Tau to search for evidence of absorption due to the R0, R1, and R2 gas-phase CH4 ν3 lines near 3.3 μm. From this, we report a 3 σ upper limit of 1.3 × 1015 cm-2 for the CH4 gas column density toward HL Tau. Our results are compared to those found for CO gas toward this source and to the recent model for chemistry in the inner (10 AU) disks around T Tauri stars by Markwick et al. We find that the upper limit of methane ice+gas …

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Interstellar H3+ Line Absorption Toward Lkhα 101, Sean D. Brittain, Theodore Simon, Craig Kulesa, Terrence W. Rettig

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We present a detection of three lines of the H+3 ion in the near-infrared spectrum of the Herbig Be star LkHalpha 101. H+3 is the principal initiator of gas-phase chemistry in interstellar clouds and can be used to constrain the ionization rate or the path length through interstellar material along the line of sight. Essentially all of the observed H+3 column of (2.2+/-0.3)×1014 cm-2 toward LkHalpha 101 originates in the same dense, dark cloud; less than 1 mag of the ~11 total magnitudes of visual extinction is attributable to diffuse material. Constraints on the density [1×104cm-3

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Beryllium Abundances In F And G Dwarfs In Praesepe And Other Young Clusters From Keck Hires Observations, Ann Merchant Boesgaard, Eric Armengaud, Jeremy R. King

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The study of both Be and Li gives useful clues about stellar internal structure. Of particular interest is the study of these light elements in open clusters, which have a known age and metallicity. In this paper we present a study of Be abundances in 10 F-type stars in Praesepe and a comprehensive discussion about Be abundances in other open clusters: Hyades, Pleiades, Per, Coma, and UMa. We have made observations of the doublet of Be ii around 3130 A˚ in Praesepe stars, using the Keck I telescope and the High Resolution Echelle Spectrometer (HIRES). Beryllium abundances were derived from …

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Oxygen In Open Cluster Dwarfs: Pleiades And M34, Simon C. Schuler, Jeremy R. King, L M. Hobbs, Marc H. Pinsonneault

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We analyze the high-excitation O I lambda7774 triplet in high-resolution, moderate signal-to-noise ratio spectra of 15 Pleiades and eight M34 open cluster dwarfs over the effective temperature range of 5048-6172 K. Relative O abundances have been derived using model atmospheres interpolated from four different sets of ATLAS9 grids. In contrast to existing non-LTE (NLTE) predictions, a dramatic increase in the O I triplet abundance with decreasing temperature is seen for both clusters, regardless of the atmospheric model. S I abundances of three Pleiades stars derived from the high-excitation lambda6053 feature mimic the O I abundance behavior. O abundances have also …

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The Host Of Grb 030323 At Z=3.372: A Very High Column Density Dla System With A Low Metallicity, P. M. Vreeswijk, S. L. Ellison, C. Ledoux, R. A. M. J. Wijers, J. P. U. Fymbo, P. Møller, A. Henden, J. Hjorth, G. Masi

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We present photometry and spectroscopy of the afterglow of GRB 030323. VLT spectra of the afterglow show damped Lyα(DLA) absorption and low- and high-ionization lines at a redshift z =3.3718 ±0.0005. The inferred neutral hy-drogen column density, log N(H i) =21.90±0.07, is larger than any (GRB- or QSO-) DLA H  column density inferred directly from Lyαin absorption. From the afterglow photometry, we derive a conservative upper limit to the host-galaxy extinction: AV <0.5 mag. The iron abundance is [Fe/H] =−1.47 ±0.11, while the metallicity of the gas as measured from sulphur is [S/H] =−1.26 ±0.20. We derive an upper limit on the H2 molecular fraction of 2N(H2)/(2N(H2) +N(H i)) <∼10−6.In the Lyαtrough, a Lyαemission line is detected, which corresponds to a star-formation rate (not corrected for dust extinction) of roughly 1 Myr−1. All these results are consistent with the host galaxy of GRB 030323 consisting of a low metallicity gas with a low dust content. We detect ﬁne-structure lines of silicon, Si*, which have never been clearly detected in QSO-DLAs; this suggests that these lines are produced in the vicinity of the GRB explosion site. Under the assumption that these ﬁne-structure levels are populated by particle collisions, we estimate the H  volume density to be nH i =102−104 cm−3.HST/ACS imaging 4 months after the burst shows an extended AB(F606W) =28.0 ±0.3 mag object at a distance of 0.14 (1 kpc) from the early afterglow location, which presumably is the host galaxy of GRB 030323.

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Full-Text Articles in Physical Sciences and Mathematics

Discovery Of The Near-Ir Afterglow And Of The Host Of Grb 030528, A. Rau, J. Greiner, S. Klose, M. Salvato, J. M. Castro Cerón, Dieter H. Hartmann, A. Fruchter, A. Levan, N. R. Tanvir, J. Gorosabel

Publications

Discovery Of Co Gas In The Inner Disk Of Tw Hydrae, Terrence W. Rettig, Joe Haywood, Theodore Simon, Sean D. Brittain, Erika Gibb

Publications

Probing A Grb Progenitor At A Redshift Of Z=2: A Comprehensive Observing Campaign Of The Afterglow Of Grb 030226, S. Klose, J. Greiner, A. Rau, A. A. Henden, Dieter H. Hartmann, A. Zeh, C. Reis, N. Masetti, D. Malesani, E. Guenther

Publications

The Correlation Of Lithium And Beryllium In F And G Cluster Dwarf Stars, Ann Merchant Boesgaard, Eric Armengaud, Constantine P. Deliyannis, Alex Stephens, Jeremy R. King

Publications

Spin Mass Of An Electron Liquid, Zhixin Qian, Giovanni Vignale, D C. Marinescu

Publications

The Li Overabundance Of J37: Diﬀusion Or Accretion?, J F. Ashwell, R D. Jeffries, C P. Deliyannis, A Steinhauer, Jeremy R. King

Publications

The Near-Infared Survey Of The N49 Region Around The Soft Gamma Repeater Sgr 0526-66, S. Klose, A. A. Henden, U. Geppert, J. Greiner, H. H. Guetter, Dieter H. Hartmann, C. Kouveliotou, C. B. Luginbuhl, B. Stecklum, F. J. Vrba

Publications

The Upper Limit For Ch4 In The Protostellar Disk Toward Hl Tauri, E L. Gibb, T Rettig, Sean D. Brittain, R Haywood, Theodore Simon, C Kulesa

Publications

Interstellar H3+ Line Absorption Toward Lkhα 101, Sean D. Brittain, Theodore Simon, Craig Kulesa, Terrence W. Rettig

Publications

Beryllium Abundances In F And G Dwarfs In Praesepe And Other Young Clusters From Keck Hires Observations, Ann Merchant Boesgaard, Eric Armengaud, Jeremy R. King

Publications

Oxygen In Open Cluster Dwarfs: Pleiades And M34, Simon C. Schuler, Jeremy R. King, L M. Hobbs, Marc H. Pinsonneault

Publications

The Host Of Grb 030323 At Z=3.372: A Very High Column Density Dla System With A Low Metallicity, P. M. Vreeswijk, S. L. Ellison, C. Ledoux, R. A. M. J. Wijers, J. P. U. Fymbo, P. Møller, A. Henden, J. Hjorth, G. Masi

Publications