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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').
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"

5039 results found.

  1. Swift GRB 200411A: Global MASTER-Net observations report
  2. GRB 200411A: Swift-XRT refined Analysis
  3. IceCube Alert 200410.97: Global MASTER-Net observations report
  4. Fermi trigger No 608204639: Global MASTER-Net observations report
  5. GRB 200410A: Swift-XRT refined Analysis
  6. Baksan Neutrino Observatory Alert 200408.26: Global MASTER-Net observations report
  7. Baksan Neutrino Observatory Alert 200409.23: Global MASTER-Net observations report
  8. GRB 200409A: Swift-XRT refined Analysis
  9. Fermi GRB 200407B: Global MASTER-Net observations report
  10. Fermi GRB 200403A: Global MASTER-Net observations report
  11. LIGO/Virgo S200224ca: Upper limits from Konus-Wind observations
  12. Fermi GRB 200402C: Global MASTER-Net observations report
  13. Fermi GRB 200402A: Global MASTER-Net observations report
  14. Fermi GRB 200401A: Global MASTER-Net observations report
  15. IPN triangulation of GRB 200327A (short)
  16. GRB 200326B: AstroSat LAXPC detection
  17. Fermi trigger No 606799116: Global MASTER-Net observations report
  18. GRB 200326A: Fermi GBM Final Real-time Localization
  19. GRB 200324A: AROMA-N Optical Observation
  20. Fermi trigger No 606840801: Global MASTER-Net observations report
  21. GRB 200324A:: TSHAO optical upper limit
  22. GRB 200324A: Swift-XRT refined Analysis
  23. Swift GRB200324.69: Global MASTER-Net observations report
  24. Fermi trigger No 606681997: Global MASTER-Net observations report
  25. LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
  26. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
  27. LIGO/Virgo S200316bj: No neutrino candidates at Pierre Auger Observatory
  28. LIGO/Virgo S200316bj: No Counterparts in DDOTI/OAN Optical Observations
  29. LIGO/Virgo S200316bj: Coverage and upper limits from MAXI/GSC observations
  30. IPN triangulation of GRB 200313A
  31. Fermi trigger No 605756501: Global MASTER-Net observations report
  32. LIGO/Virgo S200224ca: DESGW Summary of DECam Observations
  33. GRB 200310A: MAXI/GSC detection
  34. Fermi trigger No 605309224: Global MASTER-Net observations report
  35. GRB 200306C: Swift-XRT refined Analysis
  36. GRB 200306A: Swift-XRT refined Analysis
  37. LIGO/Virgo S200302c : No significant candidates in FRAM - TAROT - GRANDMA observations.
  38. Swift GRB200306.01: Global MASTER-Net observations report
  39. GRB 200303A: Swift-XRT refined Analysis
  40. LIGO/Virgo S200302c: No counterpart candidates in KAIT observations
  41. LIGO/Virgo S200302c: Coverage and upper limits from MAXI/GSC observations
  42. GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
  43. LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
  44. GRB 200228B: Swift-XRT refined Analysis
  45. GRB 200227A: Swift-XRT refined Analysis
  46. GRB 200224A: Mondy optical upper limit
  47. GRB 200227A: Fermi GBM observation
  48. LIGO/Virgo S200224ca : No significant candidates in TAROT - FRAM - GRANDMA observations
  49. LIGO/Virgo S200224ca: Upper limits from CALET observations.
  50. LIGO/Virgo S200225q: no counterpart candidate in SVOM/GWAC observations
  51. GRB 200224B: DDOTI/OAN optical observations report
  52. LIGO/Virgo S200224ca: No counterpart candidates in KAIT observations
  53. LIGO/Virgo S200224ca: GRAWITA-Campo Imperatore observations.
  54. Fermi trigger No 604231129: Global MASTER-Net observations report
  55. LIGO/Virgo S200224ca: Subaru/Hyper Suprime-Cam follow-up observations
  56. LIGO/Virgo S200224ca: No counterpart candidates in Fermi-LAT observations
  57. LIGO/Virgo S200225q: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  58. LIGO/Virgo S200224ca: upper limits from AGILE/GRID observations
  59. GRB 200224A: LCO Upper Limits
  60. LIGO/Virgo S200224ca: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  61. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  62. LIGO/Virgo S200224ca: upper limits from AGILE/MCAL observations
  63. LIGO/Virgo S200224ca: Global MASTER-Net observations report
  64. LIGO/Virgo S200224ca: Upper limits from IceCube neutrino searches
  65. LIGO/Virgo S200224ca: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  66. Correction in name: GRB 200224B and GRB 200224C (not GRB 200224A)
  67. GRB 200224A: Swift-XRT refined Analysis
  68. GRB 200224C: Fermi GBM Final Real-time Localization
  69. GRB 200224A: Tautenburg observations
  70. Fermi trigger No 604213554: Global MASTER-Net observations report
  71. GRB 200224B: Fermi GBM Final Real-time Localization
  72. GRB 200224A: Swift detection of a burst
  73. Swift GRB200224.14: Global MASTER-Net observations report
  74. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  75. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
  76. LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
  77. LIGO/Virgo S200219ac: No counterpart candidates in KAIT observations
  78. GRB 200219C: Fermi GBM Final Real-time Localization
  79. GRB 200219A: Swift-XRT refined Analysis correction
  80. GRB 200216B: Swift-XRT refined Analysis
  81. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  82. GRB 200216A: Swift/BAT detection and arcminute localization from GUANO
  83. GRB 200215A: Swift-XRT refined Analysis
  84. GRB 200215A: Fermi GBM detection
  85. LIGO/Virgo S200213t: No neutrino candidates at Pierre Auger Observatory
  86. LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
  87. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  88. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  89. LIGO/Virgo trigger S200213t: Possible host galaxies
  90. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  91. Fermi trigger No 602817262: Global MASTER-Net observations report
  92. GRB 200205B: Swift-XRT refined Analysis
  93. GRB 200205A: MAXI/GSC detection
  94. MAXI GRB200205.29: Global MASTER-Net observations report
  95. Swift GRB 200205A: Global MASTER-Net observations report
  96. Fermi trigger No 602455182: Global MASTER-Net observations report
  97. ZTF Discovery of ZTF20aajnksq: a Rapidly Fading Luminous Transient in the GRB 200128A Localiziation Region
  98. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  99. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  100. LIGO/Virgo S200128d: No counterpart candidates in KAIT observations

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