GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Unknown  (7)
  • 2020-2024  (7)
  • 1
    Online Resource
    Online Resource
    The 1.28 GHz MeerKAT DEEP2 Image
    American Astronomical Society ; 2020
    In:  The Astrophysical Journal Vol. 888, No. 2 ( 2020-01-08), p. 61-
    Details
    In: The Astrophysical Journal, American Astronomical Society, Vol. 888, No. 2 ( 2020-01-08), p. 61-
    Type of Medium: Online Resource
    ISSN: 1538-4357
    URL: Article
    DOI: 10.3847/1538-4357/ab5d2d
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2020
    detail.hit.zdb_id: 2207648-7
    detail.hit.zdb_id: 1473835-1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    The 1.28 GHz MeerKAT Galactic Center Mosaic
    American Astronomical Society ; 2022
    In:  The Astrophysical Journal Vol. 925, No. 2 ( 2022-02-01), p. 165-
    Details
    In: The Astrophysical Journal, American Astronomical Society, Vol. 925, No. 2 ( 2022-02-01), p. 165-
    Abstract: The inner ∼200 pc region of the Galaxy contains a 4 million M ⊙ supermassive black hole (SMBH), significant quantities of molecular gas, and star formation and cosmic-ray energy densities that are roughly two orders of magnitude higher than the corresponding levels in the Galactic disk. At a distance of only 8.2 kpc, the region presents astronomers with a unique opportunity to study a diverse range of energetic astrophysical phenomena, from stellar objects in extreme environments, to the SMBH and star-formation-driven feedback processes that are known to influence the evolution of galaxies as a whole. We present a new survey of the Galactic center conducted with the South African MeerKAT radio telescope. Radio imaging offers a view that is unaffected by the large quantities of dust that obscure the region at other wavelengths, and a scene of striking complexity is revealed. We produce total-intensity and spectral-index mosaics of the region from 20 pointings (144 hr on-target in total), covering 6.5 square degrees with an angular resolution of 4″ at a central frequency of 1.28 GHz. Many new features are revealed for the first time due to a combination of MeerKAT’s high sensitivity, exceptional u , v -plane coverage, and geographical vantage point. We highlight some initial survey results, including new supernova remnant candidates, many new nonthermal filament complexes, and enhanced views of the Radio Arc bubble, Sagittarius A, and Sagittarius B regions. This project is a South African Radio Astronomy Observatory public legacy survey, and the image products are made available with this article.
    Type of Medium: Online Resource
    ISSN: 0004-637X , 1538-4357
    URL: Article
    DOI: 10.3847/1538-4357/ac449a
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2022
    detail.hit.zdb_id: 2207648-7
    detail.hit.zdb_id: 1473835-1
    SSG: 16,12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    The Panchromatic Afterglow of GW170817: The Full Uniform Data Set, Modeling, Comparison with Previous Results, and Implications
    American Astronomical Society ; 2021
    In:  The Astrophysical Journal Vol. 922, No. 2 ( 2021-12-01), p. 154-
    Details
    In: The Astrophysical Journal, American Astronomical Society, Vol. 922, No. 2 ( 2021-12-01), p. 154-
    Abstract: We present the full panchromatic afterglow light-curve data of GW170817, including new radio data as well as archival optical and X-ray data, between 0.5 and 940 days post-merger. By compiling all archival data and reprocessing a subset of it, we have evaluated the impact of differences in data processing or flux determination methods used by different groups and attempted to mitigate these differences to provide a more uniform data set. Simple power-law fits to the uniform afterglow light curve indicate a t 0.86±0.04 rise, a t −1.92±0.12 decline, and a peak occurring at 155 ± 4 days. The afterglow is optically thin throughout its evolution, consistent with a single spectral index (−0.584 ± 0.002) across all epochs. This gives a precise and updated estimate of the electron power-law index, p = 2.168 ± 0.004. By studying the diffuse X-ray emission from the host galaxy, we place a conservative upper limit on the hot ionized interstellar medium density, 〈 0.01 cm −3 , consistent with previous afterglow studies. Using the late-time afterglow data we rule out any long-lived neutron star remnant having a magnetic field strength between 10 10.4 and 10 16 G. Our fits to the afterglow data using an analytical model that includes Very Long Baseline Interferometry proper motion from Mooley et al., and a structured jet model that ignores the proper motion, indicates that the proper-motion measurement needs to be considered when seeking an accurate estimate of the viewing angle.
    Type of Medium: Online Resource
    ISSN: 0004-637X , 1538-4357
    URL: Article
    DOI: 10.3847/1538-4357/ac1ffc
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2021
    detail.hit.zdb_id: 2207648-7
    detail.hit.zdb_id: 1473835-1
    SSG: 16,12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Evidence for X-Ray Emission in Excess to the Jet-afterglow Decay 3.5 yr after the Binary Neutron Star Merger GW 170817: A New Emission Component
    American Astronomical Society ; 2022
    In:  The Astrophysical Journal Letters Vol. 927, No. 1 ( 2022-03-01), p. L17-
    Details
    In: The Astrophysical Journal Letters, American Astronomical Society, Vol. 927, No. 1 ( 2022-03-01), p. L17-
    Abstract: For the first ∼3 yrs after the binary neutron star merger event GW 170817, the radio and X-ray radiation has been dominated by emission from a structured relativistic off-axis jet propagating into a low-density medium with n 〈 0.01 cm −3 . We report on observational evidence for an excess of X-ray emission at δt 〉 900 days after the merger. With L x ≈ 5 × 10 38 erg s −1 at 1234 days, the recently detected X-ray emission represents a ≥3.2 σ (Gaussian equivalent) deviation from the universal post-jet-break model that best fits the multiwavelength afterglow at earlier times. In the context of JetFit afterglow models, current data represent a departure with statistical significance ≥3.1 σ , depending on the fireball collimation, with the most realistic models showing excesses at the level of ≥3.7 σ . A lack of detectable 3 GHz radio emission suggests a harder broadband spectrum than the jet afterglow. These properties are consistent with the emergence of a new emission component such as synchrotron radiation from a mildly relativistic shock generated by the expanding merger ejecta, i.e., a kilonova afterglow. In this context, we present a set of ab initio numerical relativity binary neutron star (BNS) merger simulations that show that an X-ray excess supports the presence of a high-velocity tail in the merger ejecta, and argues against the prompt collapse of the merger remnant into a black hole. Radiation from accretion processes on the compact-object remnant represents a viable alternative. Neither a kilonova afterglow nor accretion-powered emission have been observed before, as detections of BNS mergers at this phase of evolution are unprecedented.
    Type of Medium: Online Resource
    ISSN: 2041-8205 , 2041-8213
    URL: Article
    DOI: 10.3847/2041-8213/ac504a
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2022
    detail.hit.zdb_id: 2207648-7
    detail.hit.zdb_id: 2006858-X
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    The VLA Frontier Fields Survey: Deep, High-resolution Radio Imaging of the MACS Lensing Clusters at 3 and 6 GHz
    American Astronomical Society ; 2021
    In:  The Astrophysical Journal Vol. 910, No. 2 ( 2021-04-01), p. 105-
    Details
    In: The Astrophysical Journal, American Astronomical Society, Vol. 910, No. 2 ( 2021-04-01), p. 105-
    Abstract: The Frontier Fields project is an observational campaign targeting six galaxy clusters, with the intention of using the magnification provided by gravitational lensing to study galaxies that are extremely faint or distant. We used the Karl G. Jansky Very Large Array (VLA) at 3 and 6 GHz to observe three Frontier Fields: MACS J0416.1−2403 ( z = 0.396), MACS J0717.5+3745 ( z = 0.545), and MACS J1149.5+2223 ( z = 0.543). The images reach noise levels of ∼1 μ Jy beam −1 with subarcsecond resolution (∼2.5 kpc at z = 3), providing a high-resolution view of high- z star-forming galaxies that is unbiased by dust obscuration. We generate dual-frequency continuum images at two different resolutions per band, per cluster, and derive catalogs totaling 1966 compact radio sources. Components within the areas of Hubble Space Telescope and Subaru observations are cross-matched, providing host galaxy identifications for 1296 of them. We detect 13 moderately lensed (2.1 〈 μ 〈 6.5) sources, one of which has a demagnified peak brightness of 0.9 μ Jy beam −1 , making it a candidate for the faintest radio source ever detected. There are 66 radio sources exhibiting complex morphologies, and 58 of these have host galaxy identifications. We reveal that MACS J1149.5+2223 is not a cluster with a double relic, as the western candidate relic is resolved as a double-lobed radio galaxy associated with a foreground elliptical at z = 0.24. The VLA Frontier Fields project is a public legacy survey. The image and catalog products from this work are freely available.
    Type of Medium: Online Resource
    ISSN: 0004-637X , 1538-4357
    URL: Article
    DOI: 10.3847/1538-4357/abdf61
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2021
    detail.hit.zdb_id: 2207648-7
    detail.hit.zdb_id: 1473835-1
    SSG: 16,12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    The VLA Frontier Field Survey: A Comparison of the Radio and UV/Optical Size of 0.3 ≲ z ≲ 3 Star-forming Galaxies
    American Astronomical Society ; 2021
    In:  The Astrophysical Journal Vol. 910, No. 2 ( 2021-04-01), p. 106-
    Details
    In: The Astrophysical Journal, American Astronomical Society, Vol. 910, No. 2 ( 2021-04-01), p. 106-
    Abstract: To investigate the growth history of galaxies, we measure the rest-frame radio, ultraviolet (UV), and optical sizes of 98 radio-selected, star-forming galaxies (SFGs) distributed over 0.3 ≲ z ≲ 3 with a median stellar mass of log ( M ⋆ / M ⊙ ) ≈ 10.4 . We compare the size of galaxy stellar disks, traced by rest-frame optical emission, relative to the overall extent of star formation activity that is traced by radio continuum emission. Galaxies in our sample are identified in three Hubble Frontier Fields: MACS J0416.1−2403, MACS J0717.5+3745, and MACS J1149.5+2223. Radio continuum sizes are derived from 3 and 6 GHz radio images (≲0.″6 resolution, ≈0.9 μ Jy beam −1 noise level) from the Karl G. Jansky Very Large Array. Rest-frame UV and optical sizes are derived using observations from the Hubble Space Telescope and the Advanced Camera for Surveys and Wide Field Camera 3 instruments. We find no clear dependence between the 3 GHz radio size and stellar mass of SFGs, which contrasts with the positive correlation between the UV/optical size and stellar mass of galaxies. Focusing on SFGs with log ( M ⋆ / M ⊙ ) 〉 10 , we find that the radio/UV/optical emission tends to be more compact in galaxies with high star formation rates (≳100 M ⊙ yr −1 ), suggesting that a central, compact starburst (and/or an active galactic nucleus) resides in the most luminous galaxies of our sample. We also find that the physical radio/UV/optical size of radio-selected SFGs with log( M ⋆ / M ⊙ ) 〉 10 increases by a factor of 1.5–2 from z ≈ 3 to z ≈ 0.3, yet the radio emission remains two to three times more compact than that from the UV/optical. These findings indicate that these massive, radio-selected SFGs at 0.3 ≲ z ≲ 3 tend to harbor centrally enhanced star formation activity relative to their outer disks.
    Type of Medium: Online Resource
    ISSN: 0004-637X , 1538-4357
    URL: Article
    DOI: 10.3847/1538-4357/abe876
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2021
    detail.hit.zdb_id: 2207648-7
    detail.hit.zdb_id: 1473835-1
    SSG: 16,12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 7
    Online Resource
    Online Resource
    Multicenter registry and test bed for extended outpatient hemodynamic monitoring: the hemodynamic frontiers in heart failure (HF2) initiative
    Frontiers Media SA ; 2023
    In:  Frontiers in Cardiovascular Medicine Vol. 10 ( 2023-11-29)
    Details
    In: Frontiers in Cardiovascular Medicine, Frontiers Media SA, Vol. 10 ( 2023-11-29)
    Abstract: Hemodynamic Frontiers in Heart Failure (HF 2 ) is a multicenter academic research consortium comprised of 14 US institutions with mature remote monitoring programs for ambulatory patients with heart failure (HF). The consortium developed a retrospective and prospective registry of patients implanted with a wireless pulmonary artery pressure (PAP) sensor. Goals/aims HF 2 registry collects demographic, clinical, laboratory, echocardiographic (ECHO), and hemodynamic data from patients with PAP sensors. The aims of HF 2 are to advance understanding of HF and to accelerate development of novel diagnostic and therapeutic innovations. Methods HF 2 includes adult patients implanted with a PAP sensor as per FDA indications (New York Heart Association (NYHA) Class III HF functional class with a prior hospitalization, or patients with NYHA Class II or brain natriuretic peptide (BNP) elevation without hospitalization) at a HF 2 member site between 1/1/19 to present. HF 2 registry is maintained at University of Kansas Medical Center (KUMC). The registry was approved by the institutional review board (IRB) at all participating institutions with required data use agreements. Institutions report data into the electronic registry database using REDCap, housed at KUMC. Results This initial data set includes 254 patients implanted from the start of 2019 until May 2023. At time of device implant, the cohort average age is 73 years old, 59.8% are male, 72% have NYHA Class III HF, 40% have left ventricular ejection fraction (LVEF) & lt; 40%, 35% have LVEF & gt; 50%, mean BNP is 560 pg/ml, mean N-Terminal pro-BNP (NTproBNP) is 5,490 pg/ml, mean creatinine is 1.65 mg/dl. Average baseline hemodynamics at device implant are right atrial pressure (RAP) of 11 mmHg, pulmonary artery systolic pressure (PASP) of 47 mmHg, pulmonary artery diastolic pressure (PADP) 21 mmHg, mean pulmonary artery pressure (mPAP) of 20 mmHg, pulmonary capillary wedge pressure (PCWP) of 19 mmHg, cardiac output (CO) of 5.3 L/min, and cardiac index (CI) of 2.5 L/min/m 2 . Conclusion A real-world registry of patients implanted with a PAP sensor enables long-term evaluation of hemodynamic and clinic outcomes in highly-phenotyped ambulatory HF patients, and creates a unique opportunity to validate and test novel diagnostic and therapeutic approaches to HF.
    Type of Medium: Online Resource
    ISSN: 2297-055X
    URL: Article
    DOI: 10.3389/fcvm.2023.1321415
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2023
    detail.hit.zdb_id: 2781496-8
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...