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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"

19565 results found.

  1. GRB 040423 (=H3175): A Long GRB Localized by HETE
  2. GRB040422 : I-band follow-up observation at Lulin Observatory
  3. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  4. GRB040422, BVRcIc field calibration
  5. GRB 040422,optical observation
  6. GRB 040422: a long GRB detected with INTEGRAL
  7. GRB 040403, deep optical observations
  8. MASTER: HETE Alert 3163, 3167 technical optical observation
  9. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  10. GRB 040403: Optical observations
  11. GRB 040403: a long GRB detected with INTEGRAL
  12. GRB040323: NIR Observations and Variable Object
  13. GRB 040323, a dark GRB ?
  14. GRB040223, improved XMM position
  15. GRB 031203, possible supernova
  16. MASTER: RXTE GRB040308 optical observation
  17. IBAS results on a burst from SGR1806-20
  18. RXTE GRB040229 optical observation: no candidate
  19. GRB040228 : KISO optical follow-up observation
  20. GRB 040223: Deep NIR NTT observations
  21. GRB 040223 : Optical observation (non-detection)
  22. XMM-Newton Images of GRB 040223
  23. GRB 040223, VLA observations
  24. GRB 040223: REM IJK Observations
  25. GRB 040223 XMM-Newton observation ...
  26. GRB 031203 XMM-Newton observation
  27. GRB 040223: further offline analysis
  28. GRB031111, optical observations
  29. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  30. GRB040106: refined X-ray transient position
  31. GRB040106, likely optical afterglow
  32. GRB 031220: Optical observations of Chandra X-ray sources
  33. XMM-Newton Images of GRB 040106
  34. GRB031220: observation at Univercity of Miyazaki
  35. XMM-Newton observation of GRB040106
  36. GRB 040106 : peak flux
  37. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  38. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  39. GRB 031220 : Kyoto Optical Observation
  40. GRB 031220: Subaru observation
  41. GRB 031220: Optical observation at Tokyo Tech
  42. GRB 2974 follow-up observations
  43. GRB031203, improved XMM position
  44. XMM-Newton Observations of GRB031203: Preliminary Images
  45. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  46. XMM-Newton Observation of GRB031203
  47. GRB031203: K' Photometry of the likely GRB host
  48. XMM-Newton Observation of GRB031203
  49. GRB 031203: IR NTTobservations do not confirm REM detection
  50. GRB 031203: Apparent Spectral Break
  51. GRB031203: Planned XMM-Newton observation II
  52. GRB 031203: IR REM Observations
  53. GRB031203: Optical Observations
  54. GRB 031203 XMM-Newton observation
  55. GRB031203: Planned XMM-Newton observation
  56. GRB 030329: Planned XMM-Newton Observation
  57. GRB 031111B (= H2925) : Kyoto Optical Observation
  58. IPN triangulation of GRB031107 (two large error boxes)
  59. GRB 031111, optical observations
  60. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  61. IPN triangulation of GRB031027 (small error box)
  62. Lulin optical follow-up observations of GRB031026
  63. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  64. GRB030329: radio observations at RT-22 (CrAO)
  65. IPN triangulation of GRB031016 (two large error boxes)
  66. Ongoing Bursting Activity from SGR 1806-20 detected with IBAS
  67. XRF 030824: additional observations at CFHT
  68. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  69. XRF 030723: Subaru Optical Observations
  70. A burst from SGR 1806-20 detected with IBAS
  71. XRF 030824: Early follow-up observation at Kiso observatory
  72. XRF 030723: Detection of the likely host galaxy
  73. XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM
  74. XRF030823 (=H2818): An X-Ray Flash Localized by the HETE WXM and SXC
  75. GRB030913: Subaru Optical Observations
  76. GRB 030913, optical candidate
  77. GRB 030913, BOOTES observations
  78. IPN triangulation of GRB030916 (possible short/hard GRB; large error box)
  79. GRB030913: wide field imaging (7 sq.deg) of the error box by MASTER
  80. GRB030913 (=H2849): A GRB Possibly Localized by HETE
  81. XRF 020427: Gemini-South Spectroscopic Observations of the Host
  82. XRF030824: Optical observations
  83. IBAS detection of bursts from SGR 1806-20
  84. GRB030823: optical observation at Tokyo Tech
  85. Lulin follow-up observations of GRB030823
  86. GRB 030817 = H2808 TAROT optical observations
  87. SGR 1808-20 (=H2802): A Possible new SGR
  88. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  89. XRF030723, BVRcIc field photometry update
  90. IPN triangulation of GRB030801 (large error box)
  91. GRB021206 optical counterpart upper limit
  92. XRF030723 Radio Observations
  93. XRF 030723: confirmation of fading optical counterpart
  94. XRF030723(=H2777): Chandra Observations
  95. GRB030723: Upper limits from historical observations
  96. GRB030725, possible optical transient
  97. XRF030723: Palomar observations and proposed counterpart
  98. XRF030723, BVRcIc field photometry correction
  99. XRF030723, ROTSE-III Early Observations
  100. XRF030723, BVRcIc field photometry

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