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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"

233 results found.

  1. EP250908C: GROND observation of the fading optical counterpart
  2. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limit for EP240426a
  3. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  4. EP240408a: GROND detection of a candidate counterpart
  5. X-ray transient EP240315a: GROND J-band detection
  6. GRB200120A: SRG/eROSITA discovery of X-ray afterglow
  7. GRB131018A, optical observations
  8. GRB 130420B: Fermi GBM observation
  9. GRB 130420A: Fermi GBM observation
  10. GRB 120919A: Fermi GBM detection
  11. GRB120816A: OPTIMA discovery of optical counterpart
  12. GRB 120729A: Fermi GBM observation
  13. VLT/FORS2 redshift of GRB120716A
  14. GBM triggers 120705.153 & 120705.322 were not GRBs
  15. GBM triggers 120604.526 & 120604.399 were not GRBs
  16. Fermi Gamma-ray Burst Monitor trigger 120527.573 is not a GRB
  17. GRB120404A: GROND observations show steeply decaying afterglow
  18. GRB 120212A: Fermi GBM observation
  19. GRB 111222A: Fermi GBM observations
  20. GRB 110918A: GROND detection of the afterglow candidate
  21. A new photometric resource for GRB observers
  22. Fermi Gamma-ray Burst Monitor trigger 110809.346 is not a GRB
  23. GRB 110412A: Fermi GBM observation
  24. GRB 110406A: An exceptionally bright burst detected by INTEGRAL SPI-ACS
  25. Fermi GBM trigger 319534757 (110216319) is not a GRB
  26. GRB 100528A: Fermi GBM observation
  27. Fermi/GBM trigger 295791986 - unreliable location
  28. INTEGRAL trigger 5994 / GRB 100331A: GROND detection of a variable source
  29. GROND observations of GRB100316D/SN2010bh
  30. GRB 100305A Optical Observations
  31. GRB091109A: VLT/FORS2 spectroscopic redshift
  32. GRB 091127 : GROND observations
  33. GRB 091102A: Fermi GBM observation
  34. GRB 091026: GROND Upper Limits
  35. GRB091024: VRcIc Afterglow Observations
  36. GRB 090929A: Suzaku WAM observation of the prompt emission
  37. GRB 091003A: Fermi GBM detection
  38. GRB 090929A: Fermi GBM detection
  39. GRB090922A: correction to Fermi location
  40. GRB 090922A: Fermi GBM detection
  41. GRB 090831A: Suzaku WAM observation of the prompt emission
  42. GRB 090831: Fermi GBM detection
  43. GRB 090820B: Fermi GBM detection
  44. GRB 090812: GROND Observations of the Optical/NIR Afterglow
  45. GRB 090621A: MAGIC telescope GeV observation
  46. GRB 090717B: Fermi GBM detection
  47. GRB 090720: Fermi GBM detection
  48. GRB 090706: Fermi GBM detection
  49. GRB 090630: Fermi GBM detection
  50. GRB 090625B: Fermi GBM observation
  51. GRB 090625: Fermi GBM detection
  52. GRB 090623: Fermi GBM detection
  53. GRB 090621D: Fermi GBM detection
  54. GRB 090621C: Fermi GBM detection
  55. GRB 090621: Fermi GBM observation
  56. GRB 090620: Fermi GBM detecion
  57. GRB 090529C: Fermi GBM detection
  58. GRB 090529B: Fermi GBM detection
  59. GRB090510: VLT/FORS2 spectroscopic redshift
  60. Fermi Gamma-ray Burst Monitor trigger 263649437 is not a GRB
  61. GRB 090510B: Fermi GBM detection
  62. GRB 090418A BVRcIc field calibration
  63. GRB 090423 limiting magnitudes
  64. GRB090418A Rc-band photometry
  65. GRB 090328: Fermi-LAT refined analysis
  66. GRB 090328: Fermi GBM Spectral Analysis
  67. GRB 090320A: Fermi GBM detection
  68. GRB090310: Fermi GBM detection
  69. GRB 090306C: Fermi GBM detection
  70. GRB 090303: Fermi GBM detection
  71. GRB 090304: Fermi GBM detection
  72. GRB 090213: Fermi GBM detection
  73. GRB 090107B optical observations
  74. GRB080310, BVRcIc field calibration
  75. GRB080319B, BVRcIc field calibration
  76. GRB071010B, BVRcIc field calibration
  77. GRB060418, BVRcIc field calibration
  78. GRB060124, BVRcIc field calibration
  79. Recent GRB UBVRcIc field photometry
  80. GRB050915, optical observations
  81. GRB050824, I-band imaging
  82. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  83. GRB050820a BVRcIc field photometry
  84. GRB 050801, afterglow observations
  85. GRB050730, afterglow observations
  86. GRB050709, optical observations
  87. Recent GRB BVRcIc field photometry
  88. XRF050522, BVRcIc field photometry
  89. GRB050505: AAVSO observations
  90. GRB041219, early time observations
  91. GRB041219, BVRcIc field calibration
  92. GRB041218, BVRcIc field calibration
  93. Optical transient (GRB?) in Lynx
  94. GRB041211, BVRcIc field calibration
  95. GRB040924, BVRcIc field calibration
  96. GRB041006, BVRcIc field calibration
  97. GRB 040916: Afterglow Color at Early Times
  98. XRF040916, optical observations
  99. XRF040916, Ic observations
  100. XRF040912, BVRcIc field calibration

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