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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"

26424 results found.

  1. GRB 190610A: Swift/UVOT Upper Limits
  2. GRB 190610A: Swift-XRT observations
  3. GRB 190613B: Optical observation from Asiago Schmidt
  4. GRB 190613B: GROND Detection of the Optical/NIR Afterglow
  5. GRB 190613B: Insight-HXMT/HE detection
  6. GRB 190613B: Optical observations from NOT
  7. GRB 190613B: Swift-XRT refined Analysis
  8. GRB 190613B: Swift-BAT refined analysis
  9. GRB 190613A, Swift-BAT refined analysis
  10. GRB 190613B: Swift/UVOT Detection
  11. GRB 190613A: Fermi GBM detection
  12. GRB 190613A: Swift/UVOT Detection
  13. GRB 190613B: Fermi GBM observation
  14. GRB 190611B: BALROG localization (Fermi Trigger 581986074 / GRB 190611950)
  15. GRB 190613B: Enhanced Swift-XRT position
  16. IPN Triangulation of GRB 190611B
  17. GRB 190613A: Swift-XRT refined Analysis
  18. GRB 190613A: Enhanced Swift-XRT position
  19. GRB 190613B: BALROG localization (Fermi Trigger 582115625 / GRB 190613449)
  20. GRB 190613B: Swift detection of a burst with an optical counterpart
  21. GRB 190613A: MASTER OT detection
  22. GRB 190613A: BALROG localization (Fermi Trigger 582091643 / GRB 190613172)
  23. GRB 190613A: Swift detection of a burst with an optical counterpart
  24. Fermi trigger No 581986074 Global MASTER-Net observations report
  25. GRB 190611B: Fermi GBM detection
  26. GRB 190611A: Swift-XRT refined Analysis
  27. GRB 190611A: Swift/UVOT Upper Limits
  28. GRB 190611A: Optical observations from VLT/FORS2
  29. GRB 190611A, Swift-BAT refined analysis
  30. GRB 190611A: Enhanced Swift-XRT position
  31. GRB 190611A: Swift detection of a burst
  32. GRB 190610A: Swift-BAT refined analysis
  33. GRB 190610A: Insight-HXMT/HE detection
  34. GRB190610B: BALROG localization (Fermi Trigger 581882394 / GRB 190610750)
  35. GRB 190610A: Swift detection of a short burst
  36. GRB190609A: BALROG localization (Fermi Trigger 581758450 / GRB 190609315)
  37. GRB 190606A: Insight-HXMT/HE detection
  38. LIGO/Virgo S190425z: Swift UVOT - no new sources identified, and a summary of the Swift UVOT processing of GW triggers.
  39. GRB 190604B: VLT Afterglow Detection
  40. GRB 190605B: Insight-HXMT/HE detection
  41. GRB 190604A: Insight-HXMT/HE detection
  42. GRB 190604B: Kitab observatory optical upper limit
  43. GRB 190604B: Swift-BAT refined analysis
  44. GRB 190604B: BOOTES-3 early optical limits
  45. GRB 190604B: Swift-XRT refined Analysis
  46. GRB190604B: GROWTH-India telescope followup - no optical counterpart found
  47. GRB190604B: Swift/UVOT detection
  48. GRB 190604B: Enhanced Swift-XRT position
  49. GRB190530A: Photometric follow-up with GROWTH-India telescope
  50. GRB 190604B: Swift detection of a burst
  51. Fermi trigger No 581337762 Global MASTER-Net observations report
  52. GRB190604A: BALROG localization (Fermi Trigger 581337762 / GRB 190604446)
  53. LIGO/Virgo S190602aq: Upper limits from CALET observations
  54. LIGO/Virgo S190602aq: Upper limits from Insight-HXMT/HE observations
  55. GRB 190531B: Swift/UVOT Upper Limits
  56. GRB 190530A: R-band observation from HCT
  57. LIGO/Virgo S190602aq: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  58. LIGO/Virgo S190602aq: upper limit in INTEGRAL SPI-ACS prompt observations
  59. LIGO/Virgo S190602aq: No counterpart candidates in Fermi-LAT observations
  60. LIGO/Virgo S190602aq: No counterpart candidates in the Swift/BAT Observations
  61. LIGO/Virgo S190602aq: Upper limits from Fermi-GBM Observations
  62. LIGO/Virgo S190602aq: Upper limits from AGILE-GRID observations
  63. LIGO/Virgo S190602aq: No counterpart candidate in AGILE-MCAL observations
  64. LIGO/Virgo S190602aq: Coverage and upper limits from MAXI/GSC observations
  65. LIGO/Virgo S190602aq: No neutrino counterpart candidates in ANTARES search
  66. LIGO/Virgo S190602aq: No counterpart candidates in HAWC observations
  67. LIGO/Virgo S190602aq: Identification of a GW compact binary merger candidate
  68. LIGO/Virgo S190602aq: Upper limits from IceCube neutrino searches
  69. Konus-Wind observation of extremely bright GRB 190530A
  70. GRB 190530A: Insight-HXMT/HE detection
  71. GRB 190531B: Insight-HXMT/HE detection
  72. GRB 190531B: VLT optical upper limit
  73. GRB 190530A: SAO RAS optical observations
  74. GRB 190531B: Swift-XRT afterglow detection
  75. GRB 190531B: Fermi GBM observations
  76. GRB 190530A: Swift/UVOT Detection
  77. GRB 190530A: Steep afterglow decay found by OSN
  78. Fermi Trigger 581026217 / GRB 190531840 / GRB190531A: BALROG localization
  79. GRB 190530A: Fermi GBM observation
  80. GRB 190530A: COATLI Optical Detection of the Fading Afterglow
  81. GRB 190530A: Swift-XRT afterglow detection
  82. GRB 190530A: GWAC-F30 optical detection
  83. GRB 190530A: OAJ optical detection
  84. GRB 190530A: NOT photometry and spectroscopy
  85. Fermi GRB190530.43 Global MASTER-Net observations report
  86. GRB 190530A: Bright afterglow confirmed by OSN
  87. GRB 190530A: AGILE/GRID analysis
  88. Fermi Trigger 580904353 / GRB 190530430 / GRB190530A: BALROG localization
  89. LIGO/Virgo S190521r: CNEOST follow-up observations
  90. GRB 190525A: Insight-HXMT/HE detection
  91. LIGO/Virgo S190521r: Kanata optical/NIR follow-up observations of the CNEOST Transient
  92. LIGO/Virgo S190521r: No optical counterpart from SVOM/GWAC-F30 observations.
  93. LIGO/Virgo S190521r: No optical counterpart from SVOM/GWAC observations.
  94. LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC-F30 observations.
  95. LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC observations.
  96. Konus-Wind observation of GRB 190519A
  97. LIGO/Virgo S190521g: Upper limits from Insight-HXMT/HE observations
  98. LIGO/Virgo S190521r: RATIR Optical and NIR Observations of the CNEOST Transient
  99. LIGO/Virgo S190521g: Swift/BAT Counterpart Search
  100. LIGO/Virgo S190521r: Swift/BAT Counterpart Search

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