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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"

3533 results found.

  1. GRB 170629A: Fermi GBM observation
  2. GRB 170626A: MASTER-Tunka OT detection.
  3. GRB 170626A: Swift-BAT refined analysis
  4. GRB 170626A: TNG optical observations
  5. GRB 170626A: Afterglow detection from 1.5m OSN
  6. GRB 170626A: SAO RAS possible OT detection
  7. GRB 170626A: Swift-XRT refined Analysis
  8. GRB 170626A: Swift detection of a burst
  9. IPN Triangulation of GRB 170616A (short/hard)
  10. GRB 170519A: Mondy optical observations
  11. Swift Trigger 755873: MASTER Net optical observations
  12. GRB 170519A: CrAO optical observations
  13. LIGO/Virgo G268556: optical observations and classification of Pan-STARRS1 transients
  14. LIGO/Virgo G268556: BSA radio observations at 110 MHz
  15. GRB 170511A CALET Gamma-Ray Burst Monitor detection
  16. GRB 170522A: Swift-XRT observations
  17. LIGO/Virgo G277583: UH88/SNIFS classification of ATLAS and PS1 transients
  18. GRB 170516A: Swift-BAT refined analysis
  19. LIGO/Virgo G284239: Konus-Wind observations
  20. LIGO/Virgo G284239: H.E.S.S. very-high energy gamma-ray follow-up
  21. LIGO/Virgo G284239: HAWC follow-up
  22. GRB 170428A CALET Gamma-Ray Burst Monitor detection
  23. Short GRB 170428A: MASTER-OAFA final reduction of the optical observations
  24. GRB 170428A: GROND detection of the afterglow
  25. GRB 170428A: Xinglong 2.16-m upper limit and host galaxy candidate
  26. GRB 170428A: MASTER-OAFA early optical observations
  27. GRB 170419A: Swift detection of a burst
  28. Swift Trigger 748858: a possible GRB
  29. Fermi trigger 512347439/GRB 170327A: MASTER-SAAO possible OT detection
  30. LIGO/Virgo G277583: CALET Observations
  31. GRB 170318A: Prompt enhanced Swift-XRT position
  32. IceCube-170312A: MASTER follow-up observations
  33. GRB 170317A: MITSuME Okayama Optical Observation
  34. LIGO/Virgo G277583: ATLAS coverage and transients over the first 2 days
  35. LIGO/Virgo G277583: ERRATUM LV GCN 20871: TAROT Calern (TCA) observations
  36. LIGO/Virgo G277583: TAROT Calern (TCA) observations
  37. LIGO/Virgo G277583: SVOM/Mini-GWAC observations of the initial skymap
  38. LIGO/Virgo G275404: Medicina radio follow-up of near-infrared
  39. Konus-Wind observation of GRB 170311B
  40. LIGO/Virgo G270580: optical observations and classification of PS and MASTER sources
  41. LIGO/Virgo G275697: Further Swift-XRT sources
  42. GRB 170228B CALET Gamma-Ray Burst Monitor detection
  43. LIGO/Virgo G275697: Additional iPTF Optical Transient Candidates
  44. GRB 170228B: POLAR Observation
  45. GRB 170228A: Fermi GBM observation
  46. GRB 170228A: Fermi-LAT detection
  47. LIGO/Virgo G275697: CALET Observations
  48. LIGO/Virgo G275697: MASTER automatic follow up detection
  49. LIGO/Virgo G275697: CNEOST optical observations
  50. LIGO/Virgo G275697: REM optical/NIR observations
  51. LIGO/Virgo G275404: SVOM/Mini-GWAC: Observations of initial skymap
  52. LIGO/Virgo G274296: GRAWITA-Campo Imperatore observation
  53. GRB 170222A: Swift-XRT observations
  54. IPN Triangulation of GRB 170222A (short/hard)
  55. LIGO/Virgo G274296: J-GEM optical/NIR follow-up observations
  56. LIGO/Virgo G274296: Asiago 1.82m Optical Observations
  57. LIGO/Virgo G274296: PESSTO classification of 9 Pan-STARRS transients
  58. IPN Triangulation of GRB 170219A (short/hard)
  59. LIGO/Virgo G274296: Pan-STARRS imaging and discovery of 70 transients
  60. Konus-Wind observation of GRB 170209A
  61. Correction to GCN 20640: GRB 170208B: GROND observations
  62. GRB 170208B WHT nIR candidate afterglow
  63. GRB 170208B: GROND observations
  64. LIGO/Virgo G270580: Gemini-South Spectroscopic Classification of Optical Transients
  65. GRB 170205A: Swift/UVOT Detection of a Fading Afterglow
  66. GRB 170202A: SMARTS optical/IR afterglow observations
  67. Konus-Wind observation of GRB 170202A
  68. GRB 170205A: Swift detection of a burst with an optical counterpart
  69. GRB 170202A: MITSuME Akeno Optical Observation
  70. GRB 170202A: MASTGlobal ER-Net bright OT nonmonotonic light curve
  71. GRB 170202A: Mini-MegaTORTORA upper limits
  72. GRB 170202A: Swift detection of a burst with an optical afterglow
  73. LIGO/Virgo G270580: Las Cumbres Observatory Follow-up Observations
  74. GRB 170127A: GROND Upper limits
  75. Konus-Wind observation of GRB 170126A
  76. GRB 170127B: Swift detection of a short burst
  77. LIGO/Virgo G270580: Pan-STARRS coverage and 124 optical transients
  78. GRB 170121B: MASTER early optical observations of the Swift possible XT
  79. LIGO/Virgo G270580: ATLAS coverage and 4 optical transients
  80. LIGO/Virgo G270580: Mini-MegaTORTORA follow-up observations
  81. GRB 170113A: Swift detection of a burst with an optical counterpart
  82. GRB 170111A: Swift detection of a burst
  83. Trigger 731535: Swift detection of GRS 1716-249/GRO J1719-24/V2293 Oph
  84. LIGO/Virgo G268556: Pan-STARRS1 observations and summary of transient sources
  85. Trigger 731257: Another Swift-BAT detection of GRS 1716-249/GRO J1719-24/V2293 Oph
  86. Trigger 731183: Swift detection of GRS 1716-249/GRO J1719-24/V2293 Oph
  87. LIGO/Virgo G211117 / GW151226: LOFAR follow-up
  88. LIGO/Virgo G268556: observation regions by Project Mini-GWAC of SVOM
  89. GRS 1716-249/GRO J1719-24/V2293 Oph, Swift-BAT refined analysis
  90. GRB 161220A: Swift-BAT refined analysis
  91. IPN Triangulation of GRB 161218B (long/very bright)
  92. GRB 161117A: Swift/UVOT Detection
  93. GRB 161117B: LCO optical observations
  94. GRB 161117A: VLT/X-shooter spectroscopy and redshift
  95. GRB 161117A: Swift detection of a burst with an optical counterpart
  96. GRB 161108A: TSHAO optical observations
  97. GRB 161108A: TAROT Calern observatory optical observations
  98. GRB 160928A: The first GRB detected by POLAR
  99. Konus-Wind observation of GRB 161023A
  100. Konus-Wind observation of GRB 161017A

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