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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"

19549 results found.

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

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