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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"

3039 results found.

  1. Baksan Neutrino Observatory Alert 200408.26: Global MASTER-Net observations report
  2. Fermi GRB 200407B: Global MASTER-Net observations report
  3. GRB 200404A: Fermi GBM Final Localization
  4. GRB 200404A: BALROG localization (Fermi Trigger 607712227 / GRB 200404706)
  5. Fermi GRB 200403B: Global MASTER-Net observations report
  6. Fermi GRB 200403A: Global MASTER-Net observations report
  7. GRB 200403C: Fermi GBM Final Real-time Localization
  8. LIGO/Virgo S200316bj: Upper limits from Konus-Wind observations
  9. Fermi GRB 200402C: Global MASTER-Net observations report
  10. Fermi GRB 200401A: Global MASTER-Net observations report
  11. IPN triangulation of GRB 200327A (short)
  12. Fermi trigger No 607035413: Global MASTER-Net observations report
  13. Fermi trigger No 606918292: Global MASTER-Net observations report
  14. Fermi trigger No 606840801: Global MASTER-Net observations report
  15. GRB 200324A:: TSHAO optical upper limit
  16. Fermi trigger No 606681997: Global MASTER-Net observations report
  17. LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
  18. LIGO/Virgo S200316bj: Upper limits from Insight-HXMT/HE observations
  19. Konus-Wind observation of GRB 200313B
  20. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
  21. LIGO/Virgo S200316bj: Upper limits from CALET observations
  22. LIGO/Virgo S200316bj: No neutrino candidates at Pierre Auger Observatory
  23. LIGO/Virgo S200316bj: No counterpart candidates in Fermi-LAT observations
  24. LIGO/Virgo S200316bj: no counterpart candidates in the Swift/BAT observations
  25. LIGO/Virgo S200316bj: No counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
  26. LIGO/Virgo S200316bj: upper limits from AGILE/GRID observations
  27. LIGO/Virgo S200316bj: upper limits from AGILE/MCAL observations
  28. LIGO/Virgo S200316bj: Coverage and upper limits from MAXI/GSC observations
  29. LIGO/Virgo S200316bj : no neutrino counterpart candidate in ANTARES search
  30. LIGO/Virgo S200316bj: Identification of a GW compact binary merger candidate
  31. IPN triangulation of GRB 200313B (short)
  32. SGR Swift J1818.0-1607: Swift-BAT refined analysis
  33. Fermi trigger No 605789837: Global MASTER-Net observations report
  34. GRB 200313B: Fermi GBM Final Real-time Localization
  35. Fermi trigger No 605756501: Global MASTER-Net observations report
  36. Fermi trigger No 605309224: Global MASTER-Net observations report
  37. GRB 200306A: Swift-BAT refined analysis
  38. LIGO/Virgo S200302c : No significant candidates in FRAM - TAROT - GRANDMA observations.
  39. GRB 200303A: Swift-BAT refined analysis
  40. GRB 200303A: Swift detection of a burst
  41. LIGO/Virgo S200302c: No counterpart candidates in KAIT observations
  42. LIGO/Virgo S200302c: Coverage and upper limits from MAXI/GSC observations
  43. LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
  44. GRB 200228B: Swift-BAT refined analysis
  45. LIGO/Virgo S200213t: No significant EM counterparts identified from continued GECKO observation of host galaxy candidates
  46. GRB 200228B: Swift detection of a burst
  47. GRB 200227A: Swift-BAT refined analysis
  48. GRB 200219A: ATCA 5/9 GHz radio observations
  49. LIGO/Virgo S200224ca : No significant candidates in TAROT - FRAM - GRANDMA observations
  50. Konus-Wind observation of GRB 200219C
  51. LIGO/Virgo S200225q: no counterpart candidate in SVOM/GWAC observations
  52. LIGO/Virgo S200224ca: No counterpart candidates in KAIT observations
  53. Fermi trigger No 604231129: Global MASTER-Net observations report
  54. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  55. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  56. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
  57. LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
  58. IPN triangulation of GRB 200219B (inconsistent with the LIGO/Virgo S200219ac)
  59. GRB 200219C: CALET Gamma-Ray Burst Monitor detection
  60. LIGO/Virgo S200219ac: No counterpart candidates in KAIT observations
  61. GRB 200219C: Fermi GBM detection
  62. GRB 200219C: Fermi-LAT detection
  63. GRB 200219C: Fermi GBM Final Real-time Localization
  64. GRB 200219A: Swift-XRT refined Analysis correction
  65. GRB 200219A: Swift-XRT refined Analysis
  66. GRB 200216B: Swift-BAT refined analysis
  67. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  68. LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
  69. LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
  70. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  71. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  72. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  73. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  74. Fermi trigger No 602817262: Global MASTER-Net observations report
  75. GRB 200205B: Swift-BAT refined analysis
  76. Swift J0840.7-3516 (AKA GRB 200205A): Swift-BAT refined analysis
  77. ZTF20aajnksq: Gemini-North r-band photometry
  78. GRB 200201A: Fermi GBM Final Real-time Localization
  79. IPN triangulation of GRB 200130B
  80. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  81. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  82. GRB 200130A: Fermi GBM Final Real-time Localization
  83. LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
  84. Fermi-LAT-ANTARES coincidence
  85. Fermi trigger No 601729856: Global MASTER-Net observations report
  86. Fermi trigger No 601677816: Global MASTER-Net observations report
  87. LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
  88. LIGO/Virgo S200115j : No significant candidates in TAROT - FRAM - GRANDMA observations
  89. LIGO/Virgo S200105ae: More candidates from the Zwicky Transient Facility
  90. IceCube Alert 200117.46: Global MASTER-Net observations report
  91. LIGO/Virgo S200115j: Swift-XRT sources
  92. LIGO/Virgo S200114f: ZTF Forced Photometry of the Swift Source S200114f_X2
  93. LIGO/Virgo S200112r : No significant candidates in TAROT - FRAM - GRANDMA observations.
  94. LIGO/Virgo S200115j: no counterpart candidate in SVOM/GWAC observations
  95. Baksan Neutrino Observatory Alert 200116.22: Global MASTER-Net observations report
  96. GRB 200115A: Swift-BAT refined analysis
  97. Swift GRB200115.49: Global MASTER-Net observations report
  98. LIGO/Virgo S200114f: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  99. GRB 200109A: Fermi GBM observation
  100. LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.

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