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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"

19550 results found.

  1. MASTER: RXTE GRB040308 optical observation
  2. IBAS results on a burst from SGR1806-20
  3. RXTE GRB040229 optical observation: no candidate
  4. GRB040228 : KISO optical follow-up observation
  5. GRB 040223: Deep NIR NTT observations
  6. GRB 040223 : Optical observation (non-detection)
  7. XMM-Newton Images of GRB 040223
  8. GRB 040223, VLA observations
  9. GRB 040223: REM IJK Observations
  10. GRB 040223 XMM-Newton observation ...
  11. GRB 031203 XMM-Newton observation
  12. GRB 040223: further offline analysis
  13. GRB031111, optical observations
  14. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  15. GRB040106: refined X-ray transient position
  16. GRB040106, likely optical afterglow
  17. GRB 031220: Optical observations of Chandra X-ray sources
  18. XMM-Newton Images of GRB 040106
  19. GRB031220: observation at Univercity of Miyazaki
  20. XMM-Newton observation of GRB040106
  21. GRB 040106 : peak flux
  22. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  23. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  24. GRB 031220 : Kyoto Optical Observation
  25. GRB 031220: Subaru observation
  26. GRB 031220: Optical observation at Tokyo Tech
  27. GRB 2974 follow-up observations
  28. GRB031203, improved XMM position
  29. XMM-Newton Observations of GRB031203: Preliminary Images
  30. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  31. XMM-Newton Observation of GRB031203
  32. GRB031203: K' Photometry of the likely GRB host
  33. XMM-Newton Observation of GRB031203
  34. GRB 031203: IR NTTobservations do not confirm REM detection
  35. GRB 031203: Apparent Spectral Break
  36. GRB031203: Planned XMM-Newton observation II
  37. GRB 031203: IR REM Observations
  38. GRB031203: Optical Observations
  39. GRB 031203 XMM-Newton observation
  40. GRB031203: Planned XMM-Newton observation
  41. GRB 030329: Planned XMM-Newton Observation
  42. GRB 031111B (= H2925) : Kyoto Optical Observation
  43. IPN triangulation of GRB031107 (two large error boxes)
  44. GRB 031111, optical observations
  45. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  46. IPN triangulation of GRB031027 (small error box)
  47. Lulin optical follow-up observations of GRB031026
  48. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  49. GRB030329: radio observations at RT-22 (CrAO)
  50. IPN triangulation of GRB031016 (two large error boxes)
  51. Ongoing Bursting Activity from SGR 1806-20 detected with IBAS
  52. XRF 030824: additional observations at CFHT
  53. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  54. XRF 030723: Subaru Optical Observations
  55. A burst from SGR 1806-20 detected with IBAS
  56. XRF 030824: Early follow-up observation at Kiso observatory
  57. XRF 030723: Detection of the likely host galaxy
  58. XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM
  59. XRF030823 (=H2818): An X-Ray Flash Localized by the HETE WXM and SXC
  60. GRB030913: Subaru Optical Observations
  61. GRB 030913, optical candidate
  62. GRB 030913, BOOTES observations
  63. IPN triangulation of GRB030916 (possible short/hard GRB; large error box)
  64. GRB030913: wide field imaging (7 sq.deg) of the error box by MASTER
  65. GRB030913 (=H2849): A GRB Possibly Localized by HETE
  66. XRF 020427: Gemini-South Spectroscopic Observations of the Host
  67. XRF030824: Optical observations
  68. IBAS detection of bursts from SGR 1806-20
  69. GRB030823: optical observation at Tokyo Tech
  70. Lulin follow-up observations of GRB030823
  71. GRB 030817 = H2808 TAROT optical observations
  72. SGR 1808-20 (=H2802): A Possible new SGR
  73. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  74. XRF030723, BVRcIc field photometry update
  75. IPN triangulation of GRB030801 (large error box)
  76. GRB021206 optical counterpart upper limit
  77. XRF030723 Radio Observations
  78. XRF 030723: confirmation of fading optical counterpart
  79. XRF030723(=H2777): Chandra Observations
  80. GRB030723: Upper limits from historical observations
  81. GRB030725, possible optical transient
  82. XRF030723: Palomar observations and proposed counterpart
  83. XRF030723, BVRcIc field photometry correction
  84. XRF030723, ROTSE-III Early Observations
  85. XRF030723, BVRcIc field photometry
  86. XRF 030723, optical observations
  87. XRF030723, optical observations
  88. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  89. SGR 1806-20, submm observations
  90. RXTE PCA Observations of SGR1806-20 Region
  91. GRB030329: Subaru Optical Spectroscopy
  92. GRB030329, optical observation in May
  93. IPN triangulation of GRB030626 (single large error box)
  94. IPN triangulation of GRB030626 (two large error boxes)
  95. HETE detection of burst from SGR1806-20
  96. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  97. IPN triangulation of GRB030606 (two alternate error boxes)
  98. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  99. GRB 030528: tentative NIR counterpart
  100. GRB030528(=H2724): Observations with the Chandra X-ray Observatory

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