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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"

28052 results found.

  1. GRB 030226 Optical Spectra and R,I,z' Imaging
  2. GRB: Non-Referencing of GCN Circulars.
  3. IPN triangulation of GRB030217 (small error box)
  4. GRB 030131: marginal optical detection
  5. GRB 030204: Optical Observations
  6. GRB030204 field photometry
  7. GRB020819: Kiso R and I band observations
  8. GRB030131: Candidate Optical Afterglow
  9. IPN triangulation of GRB030204 (small error box)
  10. GRB 030131, optical observations
  11. GRB 030131: afterglow candidate
  12. GRB 030115, late-time optical observations
  13. GRB030131: corrected INTEGRAL position
  14. GRB 020819: Host galaxy at Radio Position
  15. IPN triangulation of GRB030131
  16. GRB 030131 optical observations
  17. GRB 030131 optical observations
  18. A long GRB detected by INTEGRAL
  19. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  20. GRB 030115, simultaneous observations by BOOTES-1
  21. GRB 030115: IR observations with IRSF/SIRIUS
  22. IPN triangulation of GRB030115C (large error box)
  23. GRB030115, afterglow candidate
  24. GRB 021211: R-band observations at late-time
  25. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  26. GRB 030115 : Possible IR counterpart
  27. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  28. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  29. GRB 030115: APO Optical Observations
  30. Information about where HETE will be pointing
  31. VLT spectroscopy of the probable host of GRB 021211
  32. IPN triangulation of GRB030101 (two large error boxes)
  33. GRB 021211: Probable Host and Underlying Supernova
  34. GRB 021112: Evidence for Another Dark Optical Afterglow
  35. GRB 021219: OSN optical observations
  36. GRB021219, optical observations
  37. GRB021219, optical observation by MASTER
  38. VLT spectra of GRB 021211 revisited
  39. GRB021219: a long GRB localized by INTEGRAL
  40. GRB021211: APO optical observations
  41. XRF 020903 : HST observations
  42. GRB 021201: Optical Observations
  43. GRB 021211: CTIO observations
  44. GRB021211, BVRI field photometry
  45. GRB021211: Optical observations in CrAO
  46. GRB 021211, optical observations
  47. GRB021211: Kiso Observations
  48. GRB 021201, optical observations
  49. GRB021211: Optical observations
  50. GRB 021201 (short/hard), NOT observations
  51. SUB-MM SEARCH FOR GRB 021211
  52. Chandra observation of the IPN error box of GRB021201 (short/hard)
  53. GRB 021211, R- and I-band observations
  54. GRB021211 - Upper limits from recent and historical observations
  55. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  56. IPN triangulation of GRB021206 (small error box)
  57. IPN triangulation of GRB021205 (large error box)
  58. GRB021201, BVRcIc field photometry
  59. GRB 021201: BOOTES simultaneous optical observations
  60. IPN triangulation of GRB021201 (short/hard burst, small error box)
  61. GRB021004, late time optical observations
  62. GRB021004 Chandra Observation
  63. IPN detection of continued SGR1900+14 activity
  64. Improved IPN error box for GRB021125
  65. IPN BURST POSITION
  66. IPN triangulation of GRB021125 (INTEGRAL BURST)
  67. GRB021125 : A long GRB localized by INTEGRAL
  68. IPN confirmation of the reactivation of SGR1900+14
  69. GRB021113, SPI ACS observation
  70. GRB 021112: Afterglow or Variable Star?
  71. GRB021113: optical observations at Bisei
  72. GRB 021113: Evidence for a Dark Optical Afterglow
  73. GRB021112, BVRI field photometry
  74. GRB 021112: Variable Source in R-band search
  75. GRB021112: Optical Observations
  76. IPN triangulation of GRB021113 (=H2449; annulus)
  77. GRB 021113: Optical observations
  78. GRB 021112: RAPTOR Observations
  79. GRB021113 (=H2449): A Long GRB Localized by HETE
  80. GRB021112 (=H2448): A Long GRB Localized by HETE
  81. GRB 021016: Optical Observations
  82. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  83. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  84. SGR1900+14 activity, November 2-4, 2002
  85. GRB021104: optical observations
  86. Detection of activity from SGR 1900+14 with the RXTE/PCA
  87. IPN triangulation of GRB021027 (single large error box)
  88. IPN triangulation of GRB021027 (two large error boxes)
  89. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  90. GRB 021004: optical observations
  91. IPN triangulation of GRB021023 (small error boc)
  92. GRB 020813; likely host galaxy.
  93. IPN triangulation of GRB021020 (smaller error box)
  94. IPN triangulation of GRB021020
  95. GRB 021008, optical observations
  96. IPN triangulation of GRB021016 (small error box)
  97. IPN triangulation of GRB021014 (large error box)
  98. IPN triangulation of GRB021013 (single error box)
  99. GRB 021004: optical spectroscopy on Oct 11
  100. IPN triangulation of GRB021013 (two small error boxes)

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