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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

2803 results found.

  1. LIGO/Virgo S190814bv: a potential faint optical counterpart in CFHT imaging
  2. Fermi GBM-190816: No counterpart candidates in Fermi-LAT observations
  3. Fermi GBM-190816: AGILE in SAA at T0
  4. LIGO/Virgo S190814bv: SOAR spectroscopy of AT2019noq and AT2019ntn
  5. LIGO/Virgo S190814bv: Further Pan-STARRS observations and transient sources
  6. Fermi GBM-190816: Location-dependent upper limits from INTEGRAL/SPI-ACS prompt observation
  7. Fermi GBM-190816: A subthreshold GRB candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
  8. IceCube-190819A - IceCube observation of a high-energy neutrino candidate event
  9. LIGO/Virgo S190814bv: GRAWITA TNG NIR imaging of AT2019nqq and AT2019nqc
  10. LIGO/Virgo S190814bv: DG19dnjlc is not offset from its host galaxy
  11. LIGO/Virgo S190814bv: Additional candidates identified in DECam images by the DECam-GROWTH team
  12. LIGO/Virgo S190814bv: Fermi-LAT search for a high-energy gamma-ray counterpart
  13. LIGO/Virgo S190814bv: GRAWITA TNG infrared imaging of desgw-190814e, DG19sevhc and selected galaxies
  14. LIGO/VIRGO S190814bv: No candidates from ATLAS observations
  15. LIGO/Virgo S190814bv: GROND imaging of candidate galaxies
  16. LIGO/Virgo S190814bv: Candidates identified in DECam images by the DECam-GROWTH team
  17. LIGO/VIRGO S190814bv: No candidates from Pan-STARRS and non-detection of AT2019nme
  18. LIGO/Virgo S190814bv: ATLAS forced photometry non-detections of DESGW candidates
  19. LIGO/Virgo S190728q: Optical transients from Pan-STARRS coverage during first 2 nights
  20. LIGO/VIRGO S190728q: No candidate counterparts from ATLAS observations
  21. LIGO/Virgo S190728q: Photometric Redshift and Stellar Mass Estimates for the Potential Host Galaxy of Optical Counterpart Candidate ZTF19abjethn
  22. LIGO/Virgo S190728q: No counterpart candidates in Fermi-LAT observations
  23. LIGO/Virgo S190727h: No counterpart candidates in the Swift/BAT Observations
  24. LIGO/Virgo S190727h: No counterpart candidates in Fermi-LAT observations
  25. LIGO/Virgo S190727h: possible counterpart candidate in SPI-ACS/INTEGRAL
  26. LIGO/Virgo S190720a: No counterpart candidates in Fermi-LAT observations
  27. LIGO/Virgo S190718y: No counterpart candidates in Fermi-LAT observations
  28. LIGO/Virgo S190707q: No counterpart candidates in Fermi-LAT observations
  29. LIGO/Virgo S190706ai: No counterpart candidates in Fermi-LAT observations
  30. LIGO/Virgo S190701ah: No counterpart candidates in Fermi-LAT observations
  31. IceCube-190704A - IceCube observation of a high-energy neutrino candidate event
  32. LIGO/Virgo S190630ag: No counterpart candidates in Fermi-LAT observations
  33. GRB 190630B, Swift-BAT refined analysis
  34. Swift Trigger 912102: possible GRB 190630B
  35. IceCube-190629A - IceCube observation of a high-energy neutrino candidate event
  36. GRB 190627A: Swift detection of a burst
  37. Swift Trigger 911102: a possible GRB
  38. IceCube-190619A - IceCube observation of a high-energy neutrino candidate event
  39. GRB 190611A: Optical observations from VLT/FORS2
  40. GRB 190530A: Further OAJ/OSN photometry and analysis
  41. LIGO/Virgo S190602aq: upper limit in INTEGRAL SPI-ACS prompt observations
  42. LIGO/Virgo S190602aq: No counterpart candidates in Fermi-LAT observations
  43. IceCube-190504A: Kanata optical/NIR follow-up observations
  44. LIGO/Virgo S190521r: No candidate counterparts from ATLAS observations of the skymap
  45. LIGO/Virgo S190521r: Coverage and upper limits from Fermi-LAT observations
  46. LIGO/Virgo S190521g: No candidate counterpart in Fermi-LAT observations
  47. LIGO/Virgo S190519bj: Fermi-LAT search for a high-energy gamma-ray counterpart
  48. LIGO/Virgo S190517h: Fermi-LAT search for a high-energy gamma-ray counterpart
  49. LIGO/Virgo S190513bm: Fermi-LAT search for a high-energy gamma-ray counterpart
  50. LIGO/Virgo S190512at: Fermi-LAT search for a high-energy gamma-ray counterpart
  51. LIGO/Virgo S190510g: Spectroscopic Classification of DECam-GROWTH and DES-GW Candidate DG19fqqk/desgw-190510c with Magellan
  52. LIGO/Virgo S190510g: Non-detection of the OT in PGC 094244
  53. LIGO/Virgo S190510g: GRAWITA REM and Loiano optical observations
  54. LIGO/Virgo S190510g: DESGW counterpart candidates over 80% of the GW localization area
  55. LIGO/Virgo S190510g : Xinglong-60cm upper limit of the GRAWITA REM's OT
  56. LIGO/Virgo S190510g: MASTER possible OT in PGC094244 galaxy
  57. LIGO/Virgo S190510g: Fermi-LAT search for a high-energy gamma-ray counterpart
  58. LIGO-Virgo S190426c: Pan-STARRS non-detection of ZTF19aassfws
  59. LIGO/Virgo S190510g: GRAWITA REM optical observations
  60. IceCube-190504A: Swift-XRT Follow-up Observations
  61. IceCube-190504A - IceCube observation of a high-energy neutrino candidate event
  62. LIGO/Virgo S190503bf: Fermi-LAT search for a high-energy gamma-ray counterpart
  63. IceCube-190503A - IceCube observation of a high-energy neutrino candidate event
  64. LIGO/Virgo S190425z: Insight-HXMT observation and counterpart search
  65. LIGO/Virgo S190426c: Fermi-LAT search for a high-energy gamma-ray counterpart
  66. LIGO/Virgo S190425z: MASTER detection of the faint flare in SDSS Seyfert galaxy z = 0.09
  67. LIGO/Virgo S190425z: No Optical Detection of the Swift/UVOT Transient in ASAS-SN observations hours before and after discovery
  68. LIGO/Virgo S190425z: Further confirmation for the classification of PS19qp/AT 2019ebq as a supernova
  69. LIGO/Virgo S190425z: Lijiang 2.4-m Telescope Follow-up Observations
  70. LIGO/Virgo S190425z: Fermi-LAT search for a high-energy gamma-ray counterpart
  71. LIGO/Virgo S190426c: a possible lensed NS-NS merger
  72. LIGO/Virgo S190426c: Tentative Red Transient Candidate from Las Cumbres Observatory
  73. Baksan Neutrino Observatory Alert 190405.62: Global MASTER-Net:LIGO/Virgo S190425z: PanSTARR OT AT2019ebq/PS19qp
  74. LIGO/Virgo S190425z: J-GEM spectroscopic observations of AT2019ebq/PS19qp with Subaru/FOCAS
  75. LIGO/Virgo S190425z - ePESSTO+ NTT observations
  76. LIGO/Virgo S190425z: ATLAS observations of the S190425z skymap
  77. LIGO/Virgo S190425z: OVRO-LWA simultaneous low frequency radio observations of localization region
  78. LIGO/Virgo S190425z: INTEGRAL IBIS prompt observation
  79. LIGO/Virgo S190425z: further analysis of INTEGRAL data
  80. LIGO/Virgo S190421ar: Fermi-LAT search for a high-energy gamma-ray counterpart
  81. LIGO/Virgo S190425z: SAGUARO follow-up observations
  82. LIGO/Virgo S190425z: INTEGRAL SPI-ACS prompt observation
  83. GRB 190326A: Swift XRT and UVOT follow-up observations
  84. LIGO/Virgo S190412m: Fermi-LAT search for a high-energy gamma-ray counterpart
  85. LIGO/Virgo S190408an: ATLAS observations of the S190412m skymap
  86. IceCube-190331A: Swift-XRT Follow-up Observations
  87. GRB 190409A: ground analysis reveals a likely spurious event
  88. LIGO/Virgo ST190408an: Fermi-LAT search for a high-energy gamma-ray counterpart
  89. GRB 190409A: Swift detection of a possible burst
  90. LIGO/Virgo S190408an: SAGUARO follow-up observations
  91. Swift GRB 190331B: Further Swift-XRT observations
  92. GRB 190331B: Swift observations of a ground-detected burst
  93. IceCube-190331A - IceCube observation of a high-energy neutrino candidate event
  94. Further Chandra observations of GW170817 ~581-583 days since merger
  95. Swift detection of LS I +61 303
  96. Correction: Chandra observations of GW170817 ~581 days since merger
  97. Chandra observations of GW170817 ~581 days since merger
  98. GRB 190206A: AstroSat CZTI detection
  99. GRB 190203A: Swift-BAT refined analysis
  100. GRB 190204A: Swift detection of a burst with a possible optical counterpart

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