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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"

41731 results found.

  1. GRB 151118A iTelescope observation
  2. GRB 151122A: Swift/UVOT Observations
  3. GRB 151122A: Swift-XRT observations
  4. GRB 151122A: Fermi GBM detection
  5. GRB 151122A: Swift ToO observations
  6. GRB 151122A: Swift detection of a burst
  7. Konus-Wind observation of GRB 151120A
  8. GRB 151027A: Maidanak optical observations
  9. Swift-BAT refined analysis of trigger 664624 from SGR J1819-1600
  10. Swift Trigger 664610 is not astrophysical
  11. Swift-BAT probable detection of an outburst from SGR J1819-1600 (AX J1818.8-1559)
  12. Swift Trigger 664610: is unlikely a GRB
  13. GRB 151118A: MITSuME Akeno optical upper limits
  14. GRB 151120A: Swift-XRT afterglow detection
  15. GRB 151120A: Fermi GBM observation
  16. GRB 151118A: AAO optical upper limit
  17. LIGO/Virgo G194575: Updated significance from offline GW analysis
  18. GRB 151120A: Swift ToO observations
  19. GRB 151120A: GROND optical/NIR afterglow
  20. GRB 151120A: A long GRB detected by INTEGRAL
  21. GRB 151118A, Swift-BAT refined analysis
  22. LIGO/Virgo G194575: Fermi GBM Observations
  23. 610 MHz detection of GRB 151027A with the GMRT
  24. GRB 151118A: Early optical limit from pt5m, La Palma
  25. GRB 151118A: ISON-NM early optical limit
  26. GRB 151118A: Swift-XRT refined Analysis
  27. GRB 151027A: SAO RAS and Mt. Terskol observations
  28. GRB 151118A: Swift/UVOT Upper Limits
  29. GRB GRB 151118A: MASTER-NET optical observations
  30. GRB 151118A: Optical observations from OSN
  31. GRB 151118A: Swift detection of a burst
  32. Swift-BAT resumption of normal operations
  33. GRB151027A; Optical observations
  34. GMRT radio detection of GRB 151027A
  35. GRB 151114A: GROND Detection of the Optical/NIR Afterglow Candidate
  36. GRB 151114A: Swift-XRT refined Analysis
  37. GRB 151107B: CALET Gamma-Ray Burst Monitor detection
  38. GRB 151114A: Swift-BAT refined analysis
  39. GRB 151112A: GROND photometric redshift and i'-band prediction
  40. GRB 151114A: Swift/UVOT Detection
  41. GRB 151114A: LCOGT-FTS afterglow observations
  42. GRB 151114A: Swift detection of a burst with an optical counterpart
  43. GRB 151111A: GROND confirmation of the afterglow and photometric redshift estimate
  44. GRB 151112A: Swift/UVOT Upper Limits
  45. GRB 151112A: MAXI/GSC detection
  46. GRB 151112A: GROND Detection of the Optical/NIR Afterglow Candidate
  47. GRB 151112A: Swift-XRT refined Analysis
  48. GRB 151112A: Swift-BAT refined analysis
  49. GRB 151112A: MASTER-NET optical limit
  50. GRB 151112A: initial UVOT observations
  51. GRB 151112A: Swift-XRT observations
  52. GRB 151112A: Swift detection of a burst
  53. GRB 151111A: Swift/UVOT upper limits
  54. Swift-BAT trigger 663164 is not a burst.
  55. GRB 151111A: GROND marginal detection of a afterglow candidate
  56. LIGO/Virgo G194575: VLA follow-up
  57. GRB 151111A: Swift-XRT refined Analysis
  58. GRB 151111A: Fermi GBM observation
  59. GRB 151111A: LCOGT-FTS afterglow observations
  60. GRB 151111A: Swift-BAT refined analysis
  61. GRB 151111A: Swift detection of a burst
  62. IPN triangulation of GRB151107B
  63. GRB 151107B: MASTER-NET OT detection inside the FERMI error box
  64. GRB 151027A: continued Mondy optical observations
  65. GRB 151107B: Mini-MegaTORTORA limits on simultaneous optical emission
  66. LIGO/Virgo G194575: Liverpool Telescope observations of iPTF-15dld and iPTF-15dni
  67. LIGO/Virgo G194575: La Silla QUEST, Pan-STARRS and PESSTO observations of iPTF15dld
  68. GRB 151107A: Further investigation of the source nature
  69. GRB 151107B
  70. LIGO/Virgo G194575: Swift observations if iPTF15dld
  71. GRB 151107A, Swift-BAT refined analysis
  72. GRB 151027A: Hankasalmi optical observations
  73. LIGO/Virgo G194575: INAF-TNG/Asiago Telescope follow-up of iPTF15dld
  74. GRB 151107A: MASTER-NET optical observations
  75. GRB 151107A: Swift detection of a possible burst
  76. LIGO/Virgo G194575: INAF-Asiago Telescope further analysis of iPTF candidates
  77. Swift-BAT triggers are disabled
  78. LIGO/Virgo G194575: INAF-Asiago Telescope follow-up of iPTF candidates
  79. LIGO/Virgo G194575: VLA follow-up
  80. GRB 151027A: Mondy optical observations
  81. GRB 151027A: Mt. Terskol observatory optical observation
  82. LIGO/Virgo G194575: MAXI/GSC further analysis
  83. GRB 150910A: CrAO optical observations
  84. GRB 151027A: the missing GeV component
  85. GRB 151029A: FRAM optical afterglow detection
  86. LIGO/Virgo G194575: LT Spectroscopy of iPTF-15dmk
  87. GRB 151027A: Correction to GCN 18519
  88. GRB 151031A: MITSuME Akeno optical upper limits
  89. GRB 151031A: GROND observation
  90. LIGO/Virgo G194575: LT Spectroscopy of iPTF candidates
  91. GRB 151027B: ATCA radio detection
  92. GRB 151031A
  93. GRB 151031A: Swift/UVOT Detection
  94. GRB 151030A: Fermi GBM observation
  95. GRB 151031A: Swift-XRT refined Analysis
  96. GRB 151027B: RATIR Late-Time Upper Limits
  97. GRB 151031A: Swift-BAT refined analysis
  98. GRB 151031A: VLT/X-shooter optical counterpart and redshift
  99. GRB 151031A: Swift detection of a burst
  100. GRB 151027A: Continued P60 Monitoring

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