93 research outputs found

    Detecting Intracluster Gas Motion in Galaxy Clusters: Mock Astro-E2 Observations

    Full text link
    We explore the detectability of bulk motions in the X-ray emitting intracluster medium (ICM) using a catalog of 1,836 mock Astro-E2 observations of simulated clusters of galaxies. We generate high resolution mock spectra for two observing strategies: a four-pointing mosaic and a single central pointing. Normalizing to 200 (400) photons in the iron K-alpha region for the mosaic (central) study, we fit Poisson realizations of each simulated spectrum to a velocity broadened isothermal plasma emission model. We confirm that the velocity characteristics (mean and dispersion) returned by the spectral fittings are unbiased measures of the emission-weighted values within the observed region, with scatter 55 km/s. The maximum velocity difference between mosaic element pairs Δvmax\Delta v_{\rm max} has ~ 6% likelihood of being transonic (Δvmax0.5cs\Delta v_{\rm max} \ge 0.5 c_s), and the likelihood falls steeply, p \spropto (\Delta v_{\rm max}/c_s)^{-4}, at high Mach number. The velocity broadening parameter σv\sigma_v from the central pointing fit exceeds the thermal value in 49% of the cases, with again a σv4\sigma_v^{-4} tail at large dispersion. We present as case studies the clusters that yield the strongest signal for each observing strategy.Comment: 13 pages, 20 figures. Submitted to ApJ. Version with postscript figures embedded in the text available at http://www.umich.edu/~apawl/astroe2/. Version 2 includes changes in response to referee report and corrects an error in optical depth estimate

    Tallaba

    Get PDF
    Ġabra ta’ poeżiji u proża li tinkludi: Il-Bravi fid-Dar ta’ Luċija ta’ Dun Pawl – X’Qasma ta’ Qalb ta’ C. M. D – Innu ta’ G. M. A. – Ġens il-Malti ta’ R. Briffa – It-Tallaba minn ta’ Matilde Serao ta’ Ġużè Micallef GoggiN/

    Dangerous implications of a minimum length in quantum gravity

    Full text link
    The existence of a minimum length and a generalization of the Heisenberg uncertainty principle seem to be two fundamental ingredients required in any consistent theory of quantum gravity. In this letter we show that they would predict dangerous processes which are phenomenologically unacceptable. For example, long--lived virtual super--Planck mass black holes may lead to rapid proton decay. Possible solutions of this puzzle are briefly discussed.Comment: 5 pages, no figure. v3: refereed versio

    Air Raid

    Get PDF
    Ġabra ta’ poeżiji u proża li tinkludi: Dwejjaq Missirijietna ta’ Rużar Briffa – Xemx ta’ Settembru ta’ Vic. Apap – God Save the King ta’ Ġużè Galea – It-8 ta’ Settembru Londra, 1942 ta’ A. V. Vassallo – Wenzu jsib lil Luċija f’Lazzarett ta’ Dun Pawl – MDLXV ta’ Albert M. Cassola – Innu lil San Duminku ta’ Gużman – Innu lill-Bambina – Il-Għanja tar-Rebħa! ta’ N. Biancardi – Air Raid ta’ E. Agius.N/

    Suldat

    Get PDF
    Ġabra ta’ poeżiji u proża li tinkludi: Sursum Corda! ta’ R. M. B. – Tal-Qali ta’ Ġużè Ellul – Tfajla ta’ Dun Karm – Meta mort Għawdex bid-dawra ta’ Ġ. Cassar-Pullicino – Il-Maqdes tal-Mulej ta’ A. Buttigieg – Il-Barrakka ta’ Katrin ta’ P. Pawl Tabone – Ġlieġel ta’ Mary Meylak – Is-Suldat ta’ Ġużè Chetcuti.N/

    Pape satan aleppe

    Get PDF
    Ġabra ta’ poeżiji u proża li tinkludi: Qniepen idoqqu ta’ W. Gulia – Wara l-laqgħa ta’ Dun Abbondju mal-bravi ta’ Dun Pawl – Il-poeżija tiegħi ta’ Ġużè Chetcuti – Tfajjel sajjied ta’ Vincent Caruana – Huma kollox! ta’ Ġer. Azzopardi – Dun Mikiel Xerri ta’ Ġino Muscat-Azzopardi – Quddiem għalqa tal-bittieħ ta’ A. Buttigieg – Montecatini ta’ A. Cremona – Bluha ta’ mument ta’ Jos. Cassar Pullicino – Pape satan aleppe ta’ Albert M. Cassola.N/

    ROTSE All Sky Surveys for Variable Stars I: Test Fields

    Full text link
    The ROTSE-I experiment has generated CCD photometry for the entire Northern sky in two epochs nightly since March 1998. These sky patrol data are a powerful resource for studies of astrophysical transients. As a demonstration project, we present first results of a search for periodic variable stars derived from ROTSE-I observations. Variable identification, period determination, and type classification are conducted via automatic algorithms. In a set of nine ROTSE-I sky patrol fields covering about 2000 square degrees we identify 1781 periodic variable stars with mean magnitudes between m_v=10.0 and m_v=15.5. About 90% of these objects are newly identified as variable. Examples of many familiar types are presented. All classifications for this study have been manually confirmed. The selection criteria for this analysis have been conservatively defined, and are known to be biased against some variable classes. This preliminary study includes only 5.6% of the total ROTSE-I sky coverage, suggesting that the full ROTSE-I variable catalog will include more than 32,000 periodic variable stars.Comment: Accepted for publication in AJ 4/00. LaTeX manuscript. (28 pages, 11 postscript figures and 1 gif

    Liema....?

    Get PDF
    Ġabra ta’ poeżiji u proża li tinkludi: Nhar l-Akkademja f’ġieħ il-wisq Rev. Mons. C. Psaila ta’ Albert M. Cassola – Inkwiet fil-Familja ta’ Ġużè Galea – F’Jum l-Ingress tal-maħbub Arċisqof Mons. Michael Gonzi D.D., l-ewwel Metropolita ta’ Malta tal-Kan. A. Copperstone – Dwiem ta’ Eric Serracino-Inglott – L-Imdina ta’ R. Briffa – Wenzu Jfittex lil Luċija ta’ Dun Pawl – Liema....? ta’ Dun Karm.N/

    Rapid Optical Followup Observations of SGR Events with ROTSE-I

    Get PDF
    In order to observe nearly simultaneous emission from Gamma-ray Bursts (GRBs), the Robotic Optical Transient Search Experiment (ROTSE) receives triggers via the GRB Coordinates Network (GCN). Since beginning operations in March, 1998, ROTSE has also taken useful data for 10 SGR events: 8 from SGR 1900+14 and 2 from SGR 1806-20. We have searched for new or variable sources in the error regions of these SGRs and no optical counterparts were observed. Limits are in the range m_ROTSE ~ 12.5 - 15.5 during the period 20 seconds to 1 hour after the observed SGR events.Comment: 16 pages, 6 figures, accepted for publication in the Astrophysical Journa

    Infant mental health home visiting therapists- reflective supervision self- efficacy in community practice settings

    Full text link
    In recent years, there has been an increase in the research on reflective supervision, including the development of tools designed to measure reflective practice in the context of reflective supervision. The Reflective Supervision Self- Efficacy Scale for Supervisees (RSSESS) is a self- report measure that has been used in previous evaluations and is designed to assess perceived reflective practice self- efficacy for Infant Mental Health- Home Visiting (IMH- HV) therapists. Properties of the RSSESS including factor structure and reliability are explored in a first study that lays the foundation for the use of the RSSESS in an IMH- HV evaluation in the State of Michigan. IMH- HV therapists completed the RSSESS at 4 time points over a 12- month period and also completed a Clinician Profile Form that included questions about their IMH background and their work experience, including job satisfaction and burnout. Results indicated that the RSSESS is a reliable tool to measure change in reflective practice skills. IMH- HV therapists demonstrated growth in their use of reflective practice skills with families and their observational skills over the 12- month period. In addition, results indicated correlations between reflective supervision self- efficacy and job satisfaction as well as burnout.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154909/1/imhj21834.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154909/2/imhj21834_am.pd
    corecore