- ID:
- ivo://nasa.heasarc/cosbraw
- Title:
- COS-B Photon Events Catalog
- Short Name:
- COS-Braw
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The European Space Agency's satellite COS-B was dedicated to gamma-ray astronomy in the energy range 50 MeV to 5 Gev and carried a single spark chamber telescope with approximately a 20 degree field of view. COS-B operated in a highly eccentric polar orbit with apogee around 90000 km between 17 August 1975 and 25 April 1982. During this operational lifetime, COS-B made 65 observations, 15 of which were devoted to high (>20 deg) galactic latitudes. The COSBRAW database table is a log of the 65 COS-B observation intervals and contains target names, sky coordinates start times and other information taken from the final COS-B database produced by ESA in 1985. This final database consisted of three basic datasets: `OBSLI`, a dataset describing each observation period, typically a month; `OURLI`, a dataset describing each uninterrupted observation interval, lasting between 10 minutes and 10 hours; and `GAMLI`, a dataset containing records for each accepted gamma-ray photon. These three data sets were combined into FITS format images at NASA/GSFC. The images were formed by making the center pixel of a 1024 x 1024 pixel image correspond to the RA and DEC given in the `OBSLI` file. Each photon's RA and DEC was converted to a relative pixel in the image. This was done by using Aitoff projections. All the raw data from these three COS-B files are now stored in 65 FITS files accessible with BROWSE software in the database COSBRAW. The images can be accessed and plotted using XIMAGE and other columns of the FITS file extensions can be plotted with the FTOOL FPLOT. This is a service provided by NASA HEASARC .
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- ID:
- ivo://CDS.VizieR/J/ApJ/887/5
- Title:
- COS CGM compendium (CCC). III. z<=1 Ly{alpha} syst.
- Short Name:
- J/ApJ/887/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We characterize the metallicities and physical properties of cool, photoionized gas in a sample of 152 z<=1 strong Ly{alpha} forest systems (SLFSs, absorbers with 15<logN_HI_<16.2). The sample is drawn from our Cosmic Origins Spectrograph (COS) circumgalactic medium compendium (CCC), an ultraviolet survey of HI-selected circumgalactic gas around z<=1 galaxies that targets 261 absorbers with 15<logN_HI_<19. We show that the metallicity probability distribution function of the SLFSs at z<=1 is unimodal, skewed to low metallicities with a mean and median of [X/H]=-1.47 and -1.18dex. Very metal-poor gas with [X/H]{<}-1.4 represents about half of the population of absorbers with 15<logN_HI_<=18, while it is rare at higher N_HI_. Thus, there are important reservoirs of primitive (though not pristine) diffuse ionized gas around z<=1 galaxies. The photoionized gas around z<=1 galaxies is highly inhomogeneous based on the wide range of metallicities observed (-3<=[X/H]<=+0.4) and the fact that there are large metallicity variations (factors of 2 to 25) for most of the closely spaced absorbers ({Delta}v<=300km/s) along the same sightlines. These absorbers show a complex evolution with redshift and HI column density, and we identify subtle cosmic evolution effects that affect the interpretation of metallicity distributions and comparison with other absorber samples. We discuss the physical conditions and cosmic baryon and metal budgets of the CCC absorbers. Finally, we compare the CCC results to recent cosmological zoom simulations and explore the origins of the 15<logN_HI_<19 absorbers within the Evolution and Assembly of GaLaxies and their Environments (EAGLE) high-resolution simulations.
- ID:
- ivo://CDS.VizieR/J/ApJS/100/281
- Title:
- Cosmic background anisotropies
- Short Name:
- J/ApJS/100/281
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Cosmic microwave background (CMB) anisotropies and density fluctuations are calculated for flat cold dark matter (CDM) models with a wide range of parameters, viz., {OMEGA}_0,h_, and {OMEGA}_B_, for standard recombination and for various epochs of reionization. Tables of the power spectrum of CMB anisotropies in the form of C_l_ values as a function of l are presented. Although the Harrison-Zeldovich initial spectrum is assumed in these tables, we present simple approximations for obtaining the C_l_ values corresponding to a tilted spectrum from those with a Harrison-Zeldovich spectrum. Values of {sigma}_8_ are derived for the matter density spectrum, with {sigma}(10deg), fixed Q_(rms-PS) and COBE Differential Microwave Radiometer (DMR) 2yr normalizations. Simple modifications of the fitting formula for the density transfer function are given which are applicable for models with high baryon density. By using both numerical results and these fitting formulae, we calculate the relation between {sigma}_8_ and Q_(rms-PS) and find good agreement. In addition, the velocity fields are calculated.
- ID:
- ivo://CDS.VizieR/J/ApJ/820/66
- Title:
- Cosmic evolution of long gamma-ray burst luminosity
- Short Name:
- J/ApJ/820/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The cosmic evolution of gamma-ray burst (GRB) luminosity is essential for revealing the GRB physics and for using GRBs as cosmological probes. We investigate the luminosity evolution of long GRBs with a large sample of 258 Swift/BAT GRBs. By describing the peak luminosity evolution of individual GRBs as L_p_{prop.to}(1+z)^k^, we get k=1.49+/-0.19 using the nonparametric {tau} statistics method without considering observational biases of GRB trigger and redshift measurement. By modeling these biases with the observed peak flux and characterizing the peak luminosity function of long GRBs as a smoothly broken power law with a break that evolves as L_b_{prop.to}(1+z)^kb^, we obtain k_b_=1.14^+0.99^_-0.47_ through simulations based on the assumption that the long GRB rate follows the star formation rate incorporating the cosmic metallicity history. The derived k and k_b_ values are systematically smaller than those reported in previous papers. By removing the observational biases of the GRB trigger and redshift measurement based on our simulation analysis, we generate mock complete samples of 258 and 1000 GRBs to examine how these biases affect the {tau} statistics method. We get k=0.94+/-0.14 and k=0.80+/-0.09 for the two samples, indicating that these observational biases may lead to overestimating the k value. With the large uncertainty of k_b_ derived from our simulation analysis, one cannot even convincingly argue for a robust evolution feature of the GRB luminosity.
- ID:
- ivo://CDS.VizieR/J/AJ/152/50
- Title:
- Cosmicflows-3 catalog (CF3)
- Short Name:
- J/AJ/152/50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Cosmicflows database of galaxy distances that in the second edition contained 8188 entries is now expanded to 17669 entries. The major additions are 2257 distances that we have derived from the correlation between galaxy rotation and luminosity with photometry at 3.6{mu}m obtained with the Spitzer Space Telescope and 8885 distances based on the Fundamental Plane methodology from the Six Degree Field Galaxy Survey collaboration. There are minor augmentations to the Tip of the Red Giant Branch and Type Ia supernova compilations. A zero-point calibration of the supernova luminosities gives a value for the Hubble Constant of 76.2+/-3.4+/-2.7 (+/-rand.+/-sys.)km/s/Mpc. Alternatively, a restriction on the peculiar velocity monopole term representing global infall/outflow implies H_0_=75+/-2km/s/Mpc.
- ID:
- ivo://CDS.VizieR/J/AJ/146/86
- Title:
- Cosmicflows-2 catalog (CF2)
- Short Name:
- J/AJ/146/86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Cosmicflows-2 is a compilation of distances and peculiar velocities for over 8000 galaxies. Numerically the largest contributions come from the luminosity-line width correlation for spirals, the Tully-Fisher relation (TFR), and the related fundamental plane relation for E/S0 systems, but over 1000 distances are contributed by methods that provide more accurate individual distances: Cepheid, tip of the red giant branch (TRGB), surface brightness fluctuation, Type Ia supernova, and several miscellaneous but accurate procedures. Our collaboration is making important contributions to two of these inputs: TRGB and TFR. A large body of new distance material is presented. In addition, an effort is made to ensure that all the contributions, both our own and those from the literature, are on the same scale. Overall, the distances are found to be compatible with a Hubble constant H_0_=74.4+/-3.0km/s/Mpc. The great interest going forward with this data set will be with velocity field studies. Cosmicflows-2 is characterized by a great density and high accuracy of distance measures locally, falling to sparse and coarse sampling extending to z=0.1.
- ID:
- ivo://CDS.VizieR/J/MNRAS/414/2005
- Title:
- Cosmic flows observations
- Short Name:
- J/MNRAS/414/2005
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The neutral hydrogen properties of 1822 galaxies are being studied with the Green Bank 100-m and the Parkes 64-m telescopes as part of the 'Cosmic Flows' programme. Observed parameters include systemic velocities, profile linewidths and integrated fluxes. The linewidth information can be combined with the optical and infrared photometry to obtain distances. The 1822 HI observations complement an inventory of archives.
- ID:
- ivo://CDS.VizieR/J/ApJ/896/3
- Title:
- Cosmicflows-4: Tully-Fisher relation calibrations
- Short Name:
- J/ApJ/896/3
- Date:
- 07 Mar 2022 07:21:25
- Publisher:
- CDS
- Description:
- This study is a part of the Cosmicflows-4 project with the aim of measuring the distances of more than ~10000 spiral galaxies in the local universe up to ~15000km/s. New HI line width information has come primarily from the Arecibo Legacy Fast ALFA Survey. Photometry of our sample galaxies has been carried out in optical (SDSS u, g, r, i, and z) and infrared (WISE W1 and W2) bands. Inclinations have been determined using an online graphical interface accessible to a collaboration of citizen scientists. Galaxy distances are measured based on the correlation between the rotation rate of spirals and their absolute luminosity, known as the Tully-Fisher relation (TFR). In this study, we present the calibration of the TFR using a subsample of ~600 spirals located in 20 galaxy clusters. Correlations among such observables as color, surface brightness, and relative HI content are explored in an attempt to reduce the scatter about the TFR with the goal of obtaining more accurate distances. A preliminary determination of the Hubble constant from the distances and velocities of the calibrator clusters is H0=76.0+/-1.1(stat.)+/-2.3(sys.)km/s/Mpc.
- ID:
- ivo://CDS.VizieR/J/A+A/631/A40
- Title:
- Cosmic Horseshoe (J1148+1930) Ha and OIII spectra
- Short Name:
- J/A+A/631/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed analysis of the inner mass structure of the Cosmic Horseshoe (J1148+1930) strong gravitational lens system observed with the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3). In addition to the spectacular Einstein ring, this systems shows a radial arc. We obtained the redshift of the radial arc counter image z_s,r_=1.961+/-0.001 from Gemini observations. To disentangle the dark and luminous matter, we consider three different profiles for the dark matter distribution: a power-law profile, the NFW, and a generalized version of the NFW profile. For the luminous matter distribution, we base it on the observed light distribution that is fitted with three components: a point mass for the central light component resembling an active galactic nucleus, and the remaining two extended light components scaled by a constant M/L. To constrain the model further, we include published velocity dispersion measurements of the lens galaxy and perform a self-consistent lensing and axisymmetric Jeans dynamical modeling. Our model fits well to the observations including the radial arc, independent of the dark matter profile. Depending on the dark matter profile, we get a dark matter fraction between 60% and 70%. With our composite mass model we find that the radial arc helps to constrain the inner dark matter distribution of the Cosmic Horseshoe independently of the dark matter profile.
- ID:
- ivo://CDS.VizieR/J/ApJ/863/119
- Title:
- Cosmic-ray nuclei studies with Voyager, ACE & AMS-02
- Short Name:
- J/ApJ/863/119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The acceleration of cosmic-ray particles and their propagation in the Milky Way and the heliosphere tangle with each other, leading to complexity and degeneracy of the modeling of Galactic cosmic rays (GCRs). The recent measurements of the GCR spectra by Voyager-1 from outside of the heliosphere gave the first direct observation of GCRs in the local interstellar (LIS) environment. Together with the high-precision data near the Earth taken by the Advanced Composition Explorer (ACE) and AMS-02, we derive the LIS spectra of helium, lithium, beryllium, boron, carbon, and oxygen nuclei from a few MeV/n to TeV/n, using a non-parameterization method. These LIS spectra are helpful in further studying the injection and propagation parameters of GCRs. The nearly 20 years of data recorded by ACE are used to determine the solar modulation parameters over solar cycles 23 and 24, based on the force-field approximation. We find general agreements of the modulation potential with the results inferred from neutron monitors and other cosmic-ray data.