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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"

26284 results found.

  1. GRB031203: Optical Observations
  2. GRB 031203 XMM-Newton observation
  3. GRB031203: Planned XMM-Newton observation
  4. GRB 031203: further analysis of INTEGRAL data
  5. GRB 030329: Planned XMM-Newton Observation
  6. GRB 031111B (= H2925) : Kyoto Optical Observation
  7. IPN triangulation of GRB031114 (large error box)
  8. GRB 031111, optical observations
  9. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  10. GRB030929/SN2003jd association unlikely based on IPN localiztion
  11. IPN triangulation of GRB031027 (small error box)
  12. Lulin optical follow-up observations of GRB031026
  13. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  14. IPN triangulation of GRB031024 (single error box)
  15. IPN triangulation of GRB031024 (annulus)
  16. IPN triangulation of GRB031020 (large error box)
  17. XRF 030824: additional observations at CFHT
  18. SGR1806-20 bursts on 031008. Helicon detection and small error box.
  19. XRF 030723: Subaru Optical Observations
  20. XRF 030824: Early follow-up observation at Kiso observatory
  21. XRF 030824: observations at CFHT
  22. IPN triangulation of GRB030922B (large error box)
  23. XRF 030723: Detection of the likely host galaxy
  24. XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM
  25. XRF030823 (=H2818): An X-Ray Flash Localized by the HETE WXM and SXC
  26. IPN triangulation of GRB030921 (large error box)
  27. IPN triangulation of GRB030919 (large error box)
  28. GRB030913: Subaru Optical Observations
  29. GRB 030913, optical candidate
  30. GRB 030913, BOOTES observations
  31. IPN triangulation of GRB030916 (possible short/hard GRB; large error box)
  32. GRB030913: wide field imaging (7 sq.deg) of the error box by MASTER
  33. XRF 020427: Gemini-South Spectroscopic Observations of the Host
  34. XRF030824: Optical observations
  35. IPN triangulation of GRB030903 (large error box)
  36. IPN triangulation of GRB030827 (large error box)
  37. GRB030823: optical observations
  38. GRB030823: optical observation at Tokyo Tech
  39. Lulin follow-up observations of GRB030823
  40. GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN
  41. IPN detection of continued activity from SGR1806-20
  42. GRB 030817 = H2808 TAROT optical observations
  43. SGR 1808-20 (=H2802): A Possible new SGR
  44. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  45. XRF 030723: Detection of a rebrightening in the optical afterglow
  46. XRF030723, BVRcIc field photometry update
  47. IPN triangulation of GRB030801 (large error box)
  48. GRB021206 optical counterpart upper limit
  49. IPN triangulation of GRB030726 (large error box)
  50. IPN triangulation of GRB030721 (large error box)
  51. XRF030723 Radio Observations
  52. XRF 030723: confirmation of fading optical counterpart
  53. XRF030723(=H2777): Chandra Observations
  54. GRB030723: Upper limits from historical observations
  55. XRF030723: Palomar observations and proposed counterpart
  56. GRB030725 (=H2779): A Bright GRB Localized by HETE
  57. XRF030723 (= H2777): Chandra Observations Scheduled
  58. XRF030723, BVRcIc field photometry correction
  59. XRF030723, ROTSE-III Early Observations
  60. XRF030723, BVRcIc field photometry
  61. XRF 030723, optical observations
  62. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  63. Konus-Wind detection of the bursts from SGR1806-20 region
  64. SGR 1806-20, submm observations
  65. RXTE PCA Observations of SGR1806-20 Region
  66. IPN triangulation of GRB030714 (two large error boxes)
  67. IPN triangulation of GRB030715 (two large error boxes)
  68. GRB030706 triangulation (single large error box)
  69. GRB030329, optical observation in May
  70. IPN triangulation of GRB030626 (single large error box)
  71. IPN triangulation of GRB030626 (two large error boxes)
  72. GRB030329: second XMM-Newton observation
  73. GRB030329 -- RATAN-600 data in April-May
  74. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  75. IPN triangulation of GRB030606 (two alternate error boxes)
  76. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  77. GRB 030528: tentative NIR counterpart
  78. GRB030528(=H2724): Observations with the Chandra X-ray Observatory
  79. GRB030528, BVRI field photometry
  80. GRB030329, SPM optical observations
  81. GRB030528: Chandra TOO Planned
  82. GRB030528(=H2724): Revised SXC Localization
  83. GRB 030528 Bisei optical observation
  84. GRB030528 (H2724): A long GRB localized by HETE
  85. GRB 030329: Correction to GCN 2254
  86. GRB 030329: Optical Observations
  87. GRB 030528 (=H2724) Kyoto optical observation
  88. GRB 030416: Optical Observations
  89. GRB 030329 Optical Observations
  90. GRB030329: XMM-Newton observation
  91. GRB 021004: HST observations
  92. GRB030324: Further Observations of the Candidate Optical Afterglow
  93. GRB030519B (=H2716): Peak Fluxes, Fluences, and Energy Spectrum
  94. IPN triangulation of GRB030519B=H2716 (small error box)
  95. HETE GRB030329, correction to Rc Observations in Loiano
  96. GRB 030329: Optical limit (contemporaneous imaging)
  97. IPN triangulation of GRB030509 (small errror box)
  98. GRB030329, BVRI photometry
  99. GRB030429, refiend optical brightness
  100. GRB 030329: Optical limit (contemporaneous photography)

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