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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"

32508 results found.

  1. IPN upper limit to a GRB associated with SN2003L
  2. GRB 030227: Optical limit at RIKEN
  3. GRB 030226 Optical observations
  4. IPN triangulation of GRB030306 (single small error box - REVISED)
  5. GRB030226: Optical observations at Asiago
  6. IPN triangulation of GRB030306 (two small error boxes)
  7. GRB 030226: Optical observations
  8. GRB030226: Analysis of Chandra data
  9. GRB 030227: Optical observations
  10. GRB030226, BVRc observations
  11. Chandra detection of the X-ray afterglow of GRB 030226
  12. GRB 030226, further optical/NIR imaging
  13. GRB 030226: Ic Observations
  14. GRB030227: Kiso optical upper limit
  15. GRB030227, BVRcIc field photometry
  16. GRB030226, BVRcIc field calibration
  17. GRB 030227 optical afterglow
  18. GRB 030226: Steep Decline
  19. GRB 030227: Confirmed Optical Afterglow (S1-A)
  20. GRB 030226: R band polarimetric observations
  21. GRB 030226: Optical observations
  22. GRB 030227: fading of candidate optical afterglow 'S1-A'
  23. GRB030227:Optical observations
  24. GRB 20030226: Upper limits from recent and historical observations
  25. GRB 030227, possible optical counterpart of XMM-Newton source
  26. GRB030227 - faint tentative OT candidate
  27. GRB 030226, optical observations
  28. XMM-Newton observation of GRB030227
  29. GRB 030227: Kyoto optical observation
  30. GRB 030226, optical light curve
  31. GRB 030226 spectroscopy
  32. Possible break in the GRB 030226 light curve
  33. GRB030226: optical observation
  34. GRB 030226: Confirmed decay index
  35. GRB030226: ESI spectroscopy
  36. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  37. Two absorption systems in GRB 030226
  38. GRB 030226, optical observations
  39. GRB030226: optical observations and refined redshift
  40. GRB 030226, optical observations
  41. GRB 030226: Optical afterglow
  42. GRB 030217: Optical Observations at 4, 5, and 6 Days
  43. GRB: Non-Referencing of GCN Circulars.
  44. GRB030217: optical observations
  45. IPN triangulation of GRB030217 (small error box)
  46. GRB030115, WSRT radio observations - correction to GCN 1864
  47. GRB 030131: marginal optical detection
  48. GCN/INTEGRAL Mistake Fixed
  49. GRB 030204: Optical Observations
  50. GRB030204 field photometry
  51. GRB020819: Kiso R and I band observations
  52. GRB 030204: Correction to GCN 1856
  53. GRB030131: Candidate Optical Afterglow
  54. GRB 030115: Optical Observations
  55. GRB 030204, optical observations
  56. GRB 030131, optical observations
  57. GRB030131: Kiso optical limit for corrected position
  58. GRB030131: Optical limits for corrected position
  59. GRB 030131: afterglow candidate
  60. GRB 030115, late-time optical observations
  61. Type Ic SN2003L (SN/GRB?), optical spectrum
  62. GRB 020819: Host galaxy at Radio Position
  63. IPN triangulation of GRB030131 - CORRECTION
  64. IPN triangulation of GRB030131
  65. GRB030131: Optical limit
  66. GRB 030131 optical observations
  67. GRB030131: refined position
  68. GRB 030131 optical observations
  69. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  70. GRB030115 submm upper limit
  71. GRB 030115: Further IR observations with IRSF/SIRIUS
  72. Publicizing GRB Discoveries - A Message from NASA HQ
  73. GRB 030115, simultaneous observations by BOOTES-1
  74. GRB 030115: IR observations with IRSF/SIRIUS
  75. GRB030115: R-band counterpart of IR candidate
  76. GRB030115, afterglow candidate
  77. GRB 021211: R-band observations at late-time
  78. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  79. IPN triangulation of GRB030115B (small error box)
  80. GRB 030115 : Possible IR counterpart
  81. GRB 030115: Radio Observations
  82. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  83. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  84. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  85. Distribution of INTEGRAL SPI-ACS triggers
  86. GRB030115: TAROT optical observations
  87. GRB 021211: VLT spectrum
  88. GRB 030115: APO Optical Observations
  89. GRB 030115, no optical candidate
  90. GRB 030115, optical observations
  91. GRB 030115, optical candidate
  92. IPN triangulation of GRB030109 (annulus)
  93. IPN triangulation of GRB030105 (large error box)
  94. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  95. Coronas-F -Wind triangulation of GRB030102
  96. IPN triangulation of GRB030102 (annulus)
  97. VLT spectroscopy of the probable host of GRB 021211
  98. GRB021226
  99. GRB 021211: Probable Host and Underlying Supernova
  100. GRB 021226 registration by Helicon/Coronas-F

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