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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"

28054 results found.

  1. Swift Trigger 912102: possible GRB 190630B
  2. GRB 190627A: Koshka Zeiss-1000 optical counterpart observations
  3. GRB 190627A: Swift-XRT refined Analysis
  4. GRB 190627A: GMG observation at the second epoch
  5. GRB 190627A: NIR imaging from Liverpool Telescope
  6. GRB 190627A: Optical imaging and spectroscopy from Calar Alto
  7. GRB 190627A: Swift-BAT refined analysis (short-soft burst)
  8. GRB 190610A: Further Swift-XRT observations
  9. GRB 190627A: GMG observation
  10. GRB190627A: VIRT Afterglow observation
  11. GRB 190627A: NUTTelA-TAO optical observations
  12. GRB 190627A: Enhanced Swift-XRT position
  13. GRB 190627A: Swift/UVOT Detection
  14. GRB 190627A: Swift detection of a burst
  15. GRB 190622A: BALROG localization (Fermi Trigger 582886211 / GRB 190622368)
  16. Fermi-LAT Gamma-ray Observations of IceCube-190619A
  17. IceCube-190619A: No counterpart candidates in ANTARES data
  18. IceCube-190619A: IceCube additional correlated neutrino search: upper limits
  19. IceCube-190619A - HAWC follow-up
  20. GRB 190620A: BALROG localization (Fermi Trigger 582725415 / GRB 190620507)
  21. IceCube-190619A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  22. GRB 190619B: BALROG localization (Fermi Trigger 582646590 / GRB 190619595)
  23. GRB 190613A: SEDM Observations
  24. GRB 190615B: Insight-HXMT/HE detection
  25. GRB 190615A: Insight-HXMT/HE detection
  26. GRB 190613B: Kitab observatory optical upper limit
  27. GRB 190613A: Kitab and AbAO optical upper limit
  28. Fermi trigger No 582159815 Global MASTER-Net observations report
  29. GRB 190613B: SEDM Observations
  30. GRB 190613A: SEDM Observations
  31. GRB 190610A: Swift/UVOT Upper Limits
  32. GRB 190610A: Swift-XRT observations
  33. GRB 190613B: Optical observation from Asiago Schmidt
  34. GRB 190613B: GROND Detection of the Optical/NIR Afterglow
  35. GRB 190613B: Insight-HXMT/HE detection
  36. GRB 190613B: Optical observations from NOT
  37. GRB 190613B: Swift-XRT refined Analysis
  38. GRB 190613B: Swift-BAT refined analysis
  39. GRB 190613A, Swift-BAT refined analysis
  40. GRB 190613B: Swift/UVOT Detection
  41. GRB 190613A: Fermi GBM detection
  42. GRB 190613A: Swift/UVOT Detection
  43. GRB 190613B: Fermi GBM observation
  44. GRB 190611B: BALROG localization (Fermi Trigger 581986074 / GRB 190611950)
  45. GRB 190613B: Enhanced Swift-XRT position
  46. IPN Triangulation of GRB 190611B
  47. GRB 190613A: Swift-XRT refined Analysis
  48. GRB 190613A: Enhanced Swift-XRT position
  49. GRB 190613B: BALROG localization (Fermi Trigger 582115625 / GRB 190613449)
  50. GRB 190613B: Swift detection of a burst with an optical counterpart
  51. GRB 190613A: MASTER OT detection
  52. GRB 190613A: BALROG localization (Fermi Trigger 582091643 / GRB 190613172)
  53. GRB 190613A: Swift detection of a burst with an optical counterpart
  54. Fermi trigger No 581986074 Global MASTER-Net observations report
  55. GRB 190611B: Fermi GBM detection
  56. GRB 190611A: Swift-XRT refined Analysis
  57. GRB 190611A: Swift/UVOT Upper Limits
  58. GRB 190611A: Optical observations from VLT/FORS2
  59. GRB 190611A, Swift-BAT refined analysis
  60. GRB 190611A: Enhanced Swift-XRT position
  61. GRB 190611A: Swift detection of a burst
  62. GRB 190610A: Swift-BAT refined analysis
  63. GRB 190610A: Insight-HXMT/HE detection
  64. GRB190610B: BALROG localization (Fermi Trigger 581882394 / GRB 190610750)
  65. GRB 190610A: Swift detection of a short burst
  66. GRB190609A: BALROG localization (Fermi Trigger 581758450 / GRB 190609315)
  67. GRB 190606A: Insight-HXMT/HE detection
  68. LIGO/Virgo S190425z: Swift UVOT - no new sources identified, and a summary of the Swift UVOT processing of GW triggers.
  69. GRB 190604B: VLT Afterglow Detection
  70. GRB 190605B: Insight-HXMT/HE detection
  71. GRB 190604A: Insight-HXMT/HE detection
  72. GRB 190604B: Kitab observatory optical upper limit
  73. GRB 190604B: Swift-BAT refined analysis
  74. GRB 190604B: BOOTES-3 early optical limits
  75. GRB 190604B: Swift-XRT refined Analysis
  76. GRB190604B: GROWTH-India telescope followup - no optical counterpart found
  77. GRB190604B: Swift/UVOT detection
  78. GRB 190604B: Enhanced Swift-XRT position
  79. GRB190530A: Photometric follow-up with GROWTH-India telescope
  80. GRB 190604B: Swift detection of a burst
  81. Fermi trigger No 581337762 Global MASTER-Net observations report
  82. GRB190604A: BALROG localization (Fermi Trigger 581337762 / GRB 190604446)
  83. LIGO/Virgo S190602aq: Upper limits from CALET observations
  84. LIGO/Virgo S190602aq: Upper limits from Insight-HXMT/HE observations
  85. GRB 190531B: Swift/UVOT Upper Limits
  86. GRB 190530A: R-band observation from HCT
  87. LIGO/Virgo S190602aq: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  88. LIGO/Virgo S190602aq: upper limit in INTEGRAL SPI-ACS prompt observations
  89. LIGO/Virgo S190602aq: No counterpart candidates in Fermi-LAT observations
  90. LIGO/Virgo S190602aq: No counterpart candidates in the Swift/BAT Observations
  91. LIGO/Virgo S190602aq: Upper limits from Fermi-GBM Observations
  92. LIGO/Virgo S190602aq: Upper limits from AGILE-GRID observations
  93. LIGO/Virgo S190602aq: No counterpart candidate in AGILE-MCAL observations
  94. LIGO/Virgo S190602aq: Coverage and upper limits from MAXI/GSC observations
  95. LIGO/Virgo S190602aq: No neutrino counterpart candidates in ANTARES search
  96. LIGO/Virgo S190602aq: No counterpart candidates in HAWC observations
  97. LIGO/Virgo S190602aq: Identification of a GW compact binary merger candidate
  98. LIGO/Virgo S190602aq: Upper limits from IceCube neutrino searches
  99. Konus-Wind observation of extremely bright GRB 190530A
  100. GRB 190530A: Insight-HXMT/HE detection

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