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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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').
Advanced Search

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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. GRB 200228B: Swift-XRT refined Analysis
  2. Swift GRB 200228B: Global MASTER-Net observations report
  3. GRB 200228B: Swift/UVOT Upper Limits
  4. GRB 200228B: RATIR Optical Observations
  5. GRB 200228B: Fermi GBM observation
  6. GRB 200227A: RATIR Optical Observations
  7. IceCube-200227A: Upper limits from a search for additional neutrino events in IceCube
  8. GRB 200228B: KAIT Optical Upper Limit
  9. LIGO/Virgo S200224ca: Updated Sky Localization and EM Bright Classification
  10. GRB 200228C: Insight-HXMT/HE detection
  11. GRB 200228A: Fermi GBM observation
  12. GRB 200228A: Swift/BAT detection and arcminute localization from GUANO
  13. LIGO/Virgo S200213t: No significant EM counterparts identified from continued GECKO observation of host galaxy candidates
  14. GRB 200227A: Mondy optical upper limit
  15. GRB 200228B: Enhanced Swift-XRT position
  16. Fermi-LAT Gamma-ray Observations of IceCube-200227A
  17. GRB 200228B: Swift detection of a burst
  18. GRB 200228B: Fermi GBM Final Real-time Localization
  19. Fermi trigger No 604565918: Global MASTER-Net observations report
  20. GRB 200227A: Insight-HXMT/HE detection
  21. IceCube-200227A : Upper limits from Insight-HXMT/HE observations
  22. GRB 200227A: Swift-XRT refined Analysis
  23. GRB 200228A: BALROG localization (Fermi Trigger 604565918 / GRB 200228291)
  24. GRB 200228A: Fermi GBM Final Real-time Localization
  25. GRB 200227A: Swift-BAT refined analysis
  26. GRB 200219A: ATCA 5/9 GHz radio observations
  27. GRB 200227A: Swift/UVOT Upper Limits
  28. GRB 200227A: Enhanced Swift-XRT position
  29. HAWC-200216A: No Neutrino Counterpart in ANTARES Search
  30. IceCube-200227A: Upper limits from Fermi-GBM Observations
  31. GRB 200224A: Mondy optical upper limit
  32. GRB 200227A: Fermi GBM observation
  33. LIGO/Virgo S200224ca : No significant candidates in TAROT - FRAM - GRANDMA observations
  34. IceCube-200227A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  35. GRB 200227A: MITSuME Akeno optical upper limit
  36. IceCube-200227A: IceCube observation of a high-energy neutrino candidate event
  37. GRB 200227A: Swift detection of a burst
  38. GRB 200227A: Fermi GBM Final Real-time Localization
  39. LIGO/Virgo S200225q: Not observable by CALET
  40. LIGO/Virgo S200224ca: Upper limits from CALET observations.
  41. LIGO/Virgo S200224car: GRAWITA VST-ESO PARANAL observations.
  42. LIGO/Virgo S200225q: Updated Sky Localization
  43. Konus-Wind observation of GRB 200219C
  44. LIGO/Virgo S200224ca: DESGW Optical counterpart candidates from DECam
  45. Konus-Wind observation of GRB 200219A
  46. LIGO/Virgo S200219ac: Upper limits from Konus-Wind observations
  47. LIGO/Virgo S200213t: Upper limits from Konus-Wind observations
  48. LIGO/Virgo S200208q: Upper limits from Konus-Wind observations
  49. GRB 200224A: Calar Alto 2.2m optical afterglow detection
  50. LIGO/Virgo S200225q: no counterpart candidate in SVOM/GWAC observations
  51. LIGO/Virgo S200225q: Upper limits from Insight-HXMT/HE observations
  52. LIGO/Virgo S200224ca: Upper limits from Insight-HXMT/HE observations
  53. GRB 200219A: Chandra rapid ToO upper limit
  54. LIGO/Virgo S200225q: no counterpart candidates in the Swift/BAT observations
  55. LIGO/Virgo S200224ca: no counterpart candidates in the Swift/BAT observations
  56. GRB 200224B: DDOTI/OAN optical observations report
  57. LIGO/Virgo S200219ac: Updated Sky Localization
  58. LIGO/Virgo S200224ca: No counterpart candidates in KAIT observations
  59. LIGO/Virgo S200224ca: No Counterparts in DDOTI/OAN Optical Observations
  60. LIGO/Virgo S200224ca: GRAWITA-Campo Imperatore observations.
  61. IPN triangulation of GRB 200221A (short)
  62. LIGO/Virgo S200225q: Upper limits from Fermi-GBM Observations
  63. Fermi trigger No 604231129: Global MASTER-Net observations report
  64. LIGO/Virgo S200225q: No counterpart candidates in Fermi-LAT observations
  65. LIGO/Virgo S200225q: upper limits from AGILE/GRID observations
  66. LIGO/Virgo S200224ca: Subaru/Hyper Suprime-Cam follow-up observations
  67. LIGO/Virgo S200225q: upper limits from AGILE/MCAL observations
  68. LIGO/Virgo S200225q: Upper limits from IceCube neutrino searches
  69. LIGO/Virgo S200225q: No counterpart candidates in HAWC observations
  70. LIGO/Virgo S200225q : no neutrino counterpart candidate in ANTARES search
  71. LIGO/Virgo S200225q: Global MASTER-Net observations report
  72. LIGO/Virgo S200224ca: No counterpart candidates in Fermi-LAT observations
  73. LIGO/Virgo S200225q: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  74. LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
  75. LIGO/Virgo S200219ac: No counterpart candidates from Nanshan/NEXT observations
  76. LIGO/Virgo S200224ca: upper limits from AGILE/GRID observations
  77. GRB 200224A: Swift-BAT refined analysis
  78. LIGO/Virgo S200225q: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  79. LIGO/Virgo S200224ca: not observable by Fermi-GBM
  80. GRB 200224A: LCO Upper Limits
  81. LIGO/Virgo S200224ca: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  82. GRB 200224A: RATIR Optical Observations and Confirmation of the Afterglow
  83. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  84. LIGO/Virgo S200224ca: upper limits from AGILE/MCAL observations
  85. LIGO/Virgo S200224ca: Global MASTER-Net observations report
  86. LIGO/Virgo S200224ca: Upper limits from IceCube neutrino searches
  87. LIGO/Virgo S200224ca: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  88. IPN triangulation of GRB 200224C
  89. GRB 200224A: Swift/UVOT Detection
  90. Correction in name: GRB 200224B and GRB 200224C (not GRB 200224A)
  91. GRB 200219C: Swift-XRT afterglow confirmation
  92. GRB 200224A: Swift-XRT refined Analysis
  93. GRB 200224C: Fermi GBM Final Real-time Localization
  94. GRB 200224A: Tautenburg observations
  95. GRB 200224A: BOOTES-1 and 1.5m OSN optical observations
  96. Fermi trigger No 604213554: Global MASTER-Net observations report
  97. GRB 200224B: Fermi GBM Final Real-time Localization
  98. GRB 200224A: Swift detection of a burst
  99. Swift GRB200224.14: Global MASTER-Net observations report
  100. GRB 200223A: Fermi GBM Final Real-time Localization

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