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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"

3797 results found.

  1. SGR 1935+2154: MAXI/GSC detection
  2. Fermi GRB 200423A: Global MASTER-Net observations report
  3. Fermi GRB 200421A: Global MASTER-Net observations report
  4. Fermi trigger No 608935505: Global MASTER-Net observations report
  5. Fermi GRB 200415A: Global MASTER-Net observations report
  6. GRB 200412A : AstroSat CZTI detection
  7. IPN triangulation of GRB 200415A (possible Magnetar Giant Flare in Sculptor Galaxy?)
  8. Konus-Wind observation of GRB 200412A
  9. GRB 200412B: contunued AbAO optical observations
  10. IPN triangulation of GRB 200412A
  11. GRB 200412A: Fermi GBM detection
  12. GRB 200412A: BALROG localization (Fermi Trigger 608367436 / GRB 200412290)
  13. GRB 200410A: Swift/UVOT Detection
  14. Fermi trigger No 608204639: Global MASTER-Net observations report
  15. Baksan Neutrino Observatory Alert 200408.26: Global MASTER-Net observations report
  16. Fermi GRB 200407B: Global MASTER-Net observations report
  17. GRB 200404A: Fermi GBM Final Localization
  18. GRB 200404A: BALROG localization (Fermi Trigger 607712227 / GRB 200404706)
  19. Fermi GRB 200403B: Global MASTER-Net observations report
  20. Fermi GRB 200403A: Global MASTER-Net observations report
  21. GRB 200403C: Fermi GBM Final Real-time Localization
  22. LIGO/Virgo S200316bj: Upper limits from Konus-Wind observations
  23. Fermi GRB 200402C: Global MASTER-Net observations report
  24. Fermi GRB 200401A: Global MASTER-Net observations report
  25. IPN triangulation of GRB 200327A (short)
  26. Fermi trigger No 607035413: Global MASTER-Net observations report
  27. Fermi trigger No 606918292: Global MASTER-Net observations report
  28. Fermi trigger No 606840801: Global MASTER-Net observations report
  29. GRB 200324A:: TSHAO optical upper limit
  30. Fermi trigger No 606681997: Global MASTER-Net observations report
  31. GRB 200320B: MAXI/GSC detection
  32. LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
  33. LIGO/Virgo S200316bj: Upper limits from Insight-HXMT/HE observations
  34. Konus-Wind observation of GRB 200313B
  35. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
  36. LIGO/Virgo S200316bj: Upper limits from CALET observations
  37. LIGO/Virgo S200316bj: No neutrino candidates at Pierre Auger Observatory
  38. LIGO/Virgo S200316bj: No counterpart candidates in Fermi-LAT observations
  39. LIGO/Virgo S200316bj: no counterpart candidates in the Swift/BAT observations
  40. LIGO/Virgo S200316bj: No counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
  41. LIGO/Virgo S200316bj: upper limits from AGILE/GRID observations
  42. LIGO/Virgo S200316bj: upper limits from AGILE/MCAL observations
  43. LIGO/Virgo S200316bj: Coverage and upper limits from MAXI/GSC observations
  44. LIGO/Virgo S200316bj : no neutrino counterpart candidate in ANTARES search
  45. LIGO/Virgo S200316bj: Identification of a GW compact binary merger candidate
  46. IPN triangulation of GRB 200313B (short)
  47. SGR Swift J1818.0-1607: Swift-BAT refined analysis
  48. Fermi trigger No 605789837: Global MASTER-Net observations report
  49. GRB 200313B: Fermi GBM Final Real-time Localization
  50. Fermi trigger No 605756501: Global MASTER-Net observations report
  51. LIGO/Virgo S200311bg: Coverage and upper limits from MAXI/GSC observations
  52. GRB 200310A: MAXI/GSC detection
  53. Fermi trigger No 605309224: Global MASTER-Net observations report
  54. GRB 200306A: Swift-BAT refined analysis
  55. LIGO/Virgo S200302c : No significant candidates in FRAM - TAROT - GRANDMA observations.
  56. GRB 200303A: Swift-BAT refined analysis
  57. GRB 200303A: Swift detection of a burst
  58. LIGO/Virgo S200302c: No counterpart candidates in KAIT observations
  59. LIGO/Virgo S200302c: Coverage and upper limits from MAXI/GSC observations
  60. LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
  61. GRB 200228B: Swift-BAT refined analysis
  62. LIGO/Virgo S200213t: No significant EM counterparts identified from continued GECKO observation of host galaxy candidates
  63. GRB 200228B: Swift detection of a burst
  64. GRB 200227A: Swift-BAT refined analysis
  65. GRB 200219A: ATCA 5/9 GHz radio observations
  66. LIGO/Virgo S200224ca : No significant candidates in TAROT - FRAM - GRANDMA observations
  67. Konus-Wind observation of GRB 200219C
  68. LIGO/Virgo S200225q: no counterpart candidate in SVOM/GWAC observations
  69. LIGO/Virgo S200224ca: No counterpart candidates in KAIT observations
  70. Fermi trigger No 604231129: Global MASTER-Net observations report
  71. LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
  72. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  73. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  74. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
  75. LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
  76. IPN triangulation of GRB 200219B (inconsistent with the LIGO/Virgo S200219ac)
  77. GRB 200219C: CALET Gamma-Ray Burst Monitor detection
  78. LIGO/Virgo S200219ac: No counterpart candidates in KAIT observations
  79. GRB 200219C: Fermi GBM detection
  80. GRB 200219C: Fermi-LAT detection
  81. GRB 200219C: Fermi GBM Final Real-time Localization
  82. GRB 200219A: Swift-XRT refined Analysis correction
  83. GRB 200219A: Swift-XRT refined Analysis
  84. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  85. GRB 200216B: Swift-BAT refined analysis
  86. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  87. LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
  88. LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
  89. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  90. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  91. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  92. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  93. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  94. LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
  95. Fermi trigger No 602817262: Global MASTER-Net observations report
  96. GRB 200205B: Swift-BAT refined analysis
  97. Swift J0840.7-3516 (AKA GRB 200205A): Swift-BAT refined analysis
  98. GRB 200205A = Swift J0840.7-3516, A newly discovered transient X-ray Pulsar
  99. GRB 200205A / Swift trigger 954304: VLT optical observations
  100. GRB 200205A: MAXI/GSC detection

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