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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"

28092 results found.

  1. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  2. LIGO/Virgo S200213t: MANGROVE catalog galaxy ranking
  3. LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations
  4. LIGO/Virgo S200213t: upper limits from AGILE/GRID observations
  5. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  6. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  7. LIGO/VIRGO S200213t: upper limits from AGILE/MCAL observations
  8. LIGO/Virgo S200213t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  9. LIGO/Virgo S200213t : no neutrino counterpart candidate in ANTARES search
  10. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  11. LIGO/Virgo S200213t: 1 counterpart neutrino candidate from IceCube neutrino searches
  12. LIGO/Virgo S200213t: Identification of a GW compact binary merger candidate
  13. ZTF20aajnksq: Upper limits from Konus-Wind observations
  14. LIGO/Virgo S200208q: Updated Sky Localization
  15. GRB 200131A: Tautenburg observations
  16. Konus-Wind observation of GRB 200205B
  17. GRB 200211A: BALROG localization (Fermi Trigger 603098793 / GRB 200211310)
  18. LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
  19. LIGO/Virgo S200129m: Upper limits from Insight-HXMT/HE observations
  20. GRB 200120A: Fermi GBM observation
  21. LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
  22. LIGO/Virgo S200208q: no counterpart candidates in the Swift/BAT observations
  23. LIGO/Virgo S200208q: Upper limits from Fermi-GBM Observations
  24. LIGO/Virgo S200208q : upper limits from AGILE/GRID observations
  25. LIGO/Virgo S200208q: upper limits from AGILE/MCAL observations
  26. LIGO/Virgo S200208q: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  27. LIGO/Virgo S200208q: No counterpart candidates in HAWC observations
  28. LIGO/Virgo S200208q : no neutrino counterpart candidate in ANTARES search
  29. LIGO/Virgo S200208q: Upper limits from IceCube neutrino searches
  30. LIGO/Virgo S200208q: Identification of a GW compact binary merger candidate
  31. GRB 200205B: Swift-BAT refined analysis
  32. Swift J0840.7-3516 (AKA GRB 200205A): Swift-BAT refined analysis
  33. Fermi trigger No 602731380: Global MASTER-Net observations report
  34. Swift Trigger 954840 is not a GRB
  35. GRB 200205B: Swift/UVOT Detection
  36. GRB 200205B: Swift-XRT refined Analysis
  37. GRB 200205A = Swift J0840.7-3516, A newly discovered transient X-ray Pulsar
  38. GRB 200205B: Enhanced Swift-XRT position
  39. GRB 200205A: Enhanced Swift-XRT position
  40. GRB 200205B: LCO Optical Detection
  41. GRB 200205B: Swift detection of a burst with optical counterpart
  42. Swift GRB200205.81: Global MASTER-Net OT detection
  43. GRB200120A: SRG/eROSITA discovery of X-ray afterglow
  44. GRB 200205A: REM optical observations
  45. MAXI GRB200205.29: Global MASTER-Net observations report
  46. GRB 200205A: Swift detection of a burst with a possible UV counterpart
  47. LIGO/Virgo S200129m: Upper limits from Konus-Wind observations
  48. LIGO/Virgo S200128d: Upper limits from Konus-Wind observations
  49. GRB 200131A: Further RATIR Optical Observations
  50. AMON IceCube-HAWC_200202A : No neutrino counterpart seen with ANTARES
  51. GRB 200131A: Swift-BAT refined analysis
  52. GRB 200131A: ISON-Castelgrande optical observations
  53. GRB 200131A: CDK700 optical observations
  54. GRB 200131A: Swift/UVOT Detection
  55. GRB 200131A: Swift-XRT refined Analysis
  56. GRB 200131A: VIRT optical transient detection
  57. GRB 200131A: LCO Optical Detection
  58. GRB 200131A: RATIR Optical Observations
  59. GRB 200131A: Enhanced Swift-XRT position
  60. GRB 200201A: Fermi GBM Final Real-time Localization
  61. GRB 200131A: Swift detection of a burst with an optical counterpart
  62. Konus-Wind observation of GRB 200130B
  63. IPN triangulation of GRB 200130B
  64. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  65. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  66. GRB 200130B: BALROG localization (Fermi Trigger 602071201 / GRB 200130417)
  67. LIGO/Virgo S200129m: Upper limits from CALET observations.
  68. LIGO/Virgo S200129m: no counterpart candidates in the Swift/BAT observations
  69. GRB 200127A: Swift-BAT refined analysis
  70. LIGO/Virgo S200129m: No counterpart candidates in Fermi-LAT observations
  71. LIGO/Virgo S200129m: Not observable by Fermi-GBM
  72. Konus-Wind observation of GRB 200125A
  73. LIGO/Virgo S200128d: upper limits from AGILE/GRID observations
  74. LIGO/Virgo S200129m: upper limits from AGILE/GRID observations
  75. LIGO/Virgo S200129m: upper limits from AGILE/MCAL observations
  76. LIGO/Virgo S200129m: Coverage and upper limits from MAXI/GSC observations
  77. LIGO/Virgo S200129m: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  78. LIGO/Virgo S200129m: Upper limits from IceCube neutrino searches
  79. LIGO/Virgo S200129m: Identification of a GW compact binary merger candidate
  80. LIGO/Virgo S200128d: No counterpart candidates in Fermi-LAT observations
  81. LIGO/Virgo S200128d: no counterpart candidates in the Swift/BAT observations
  82. Fermi-LAT ANTARES 200127.79 coincidence: MASTER alert observation and presence of young pulsar close to error-box
  83. GRB 200127A: Swift/UVOT Upper Limits
  84. LIGO/Virgo S200128d: Upper limits from Fermi-GBM Observations
  85. Fermi-LAT-ANTARES coincidence
  86. GRB 200127A: Mondy optical upper limit
  87. GRB200127A: Nordic Optical telecope optical upper limit
  88. LIGO/Virgo S200128d : no neutrino counterpart candidate in ANTARES search
  89. GRB 200125B: DDOTI/OAN optical observations report
  90. LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
  91. LIGO/Virgo S200128d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  92. LIGO/Virgo S200128d: No counterpart candidates in HAWC observations
  93. LIGO/Virgo S200128d: Identification of a GW compact binary merger candidate
  94. LIGO/Virgo S200128d: Upper limits from IceCube neutrino searches
  95. GRB 200127A: Nanshan-0.6m optical upper limit
  96. GRB 200127A: Enhanced Swift-XRT position
  97. GRB 200127A: Swift-XRT refined Analysis
  98. GRB 200127A: AbAO optical upper limit
  99. GRB 200125A: Swift-BAT refined analysis
  100. GRB 200127A: Swift detection of a burst

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