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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"

28056 results found.

  1. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  2. GRB 030226 simultaneous optical observations
  3. GRB 030226, optical observations
  4. GRB030226: Optical decay index
  5. GRB 030226 Optical Spectra and R,I,z' Imaging
  6. GRB: Non-Referencing of GCN Circulars.
  7. IPN triangulation of GRB030217 (small error box)
  8. GRB 030131: marginal optical detection
  9. GRB 030204: Optical Observations
  10. GRB030204 field photometry
  11. GRB020819: Kiso R and I band observations
  12. GRB030131: Candidate Optical Afterglow
  13. IPN triangulation of GRB030204 (small error box)
  14. GRB 030131, optical observations
  15. GRB 030131: afterglow candidate
  16. GRB 030115, late-time optical observations
  17. GRB030131: corrected INTEGRAL position
  18. GRB 020819: Host galaxy at Radio Position
  19. IPN triangulation of GRB030131
  20. GRB 030131 optical observations
  21. GRB 030131 optical observations
  22. A long GRB detected by INTEGRAL
  23. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  24. GRB 030115, simultaneous observations by BOOTES-1
  25. GRB 030115: IR observations with IRSF/SIRIUS
  26. IPN triangulation of GRB030115C (large error box)
  27. GRB030115, afterglow candidate
  28. GRB 021211: R-band observations at late-time
  29. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  30. GRB 030115 : Possible IR counterpart
  31. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  32. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  33. GRB 030115: APO Optical Observations
  34. Information about where HETE will be pointing
  35. VLT spectroscopy of the probable host of GRB 021211
  36. IPN triangulation of GRB030101 (two large error boxes)
  37. GRB 021211: Probable Host and Underlying Supernova
  38. GRB 021112: Evidence for Another Dark Optical Afterglow
  39. GRB 021219: OSN optical observations
  40. GRB021219, optical observations
  41. GRB021219, optical observation by MASTER
  42. VLT spectra of GRB 021211 revisited
  43. GRB021219: a long GRB localized by INTEGRAL
  44. GRB021211: APO optical observations
  45. XRF 020903 : HST observations
  46. GRB 021201: Optical Observations
  47. GRB 021211: CTIO observations
  48. GRB021211, BVRI field photometry
  49. GRB021211: Optical observations in CrAO
  50. GRB 021211, optical observations
  51. GRB021211: Kiso Observations
  52. GRB 021201, optical observations
  53. GRB021211: Optical observations
  54. GRB 021201 (short/hard), NOT observations
  55. SUB-MM SEARCH FOR GRB 021211
  56. Chandra observation of the IPN error box of GRB021201 (short/hard)
  57. GRB 021211, R- and I-band observations
  58. GRB021211 - Upper limits from recent and historical observations
  59. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  60. IPN triangulation of GRB021206 (small error box)
  61. IPN triangulation of GRB021205 (large error box)
  62. GRB021201, BVRcIc field photometry
  63. GRB 021201: BOOTES simultaneous optical observations
  64. IPN triangulation of GRB021201 (short/hard burst, small error box)
  65. GRB021004, late time optical observations
  66. GRB021004 Chandra Observation
  67. IPN detection of continued SGR1900+14 activity
  68. Improved IPN error box for GRB021125
  69. IPN BURST POSITION
  70. IPN triangulation of GRB021125 (INTEGRAL BURST)
  71. GRB021125 : A long GRB localized by INTEGRAL
  72. IPN confirmation of the reactivation of SGR1900+14
  73. GRB021113, SPI ACS observation
  74. GRB 021112: Afterglow or Variable Star?
  75. GRB021113: optical observations at Bisei
  76. GRB 021113: Evidence for a Dark Optical Afterglow
  77. GRB021112, BVRI field photometry
  78. GRB 021112: Variable Source in R-band search
  79. GRB021112: Optical Observations
  80. IPN triangulation of GRB021113 (=H2449; annulus)
  81. GRB 021113: Optical observations
  82. GRB 021112: RAPTOR Observations
  83. GRB021113 (=H2449): A Long GRB Localized by HETE
  84. GRB021112 (=H2448): A Long GRB Localized by HETE
  85. GRB 021016: Optical Observations
  86. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  87. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  88. SGR1900+14 activity, November 2-4, 2002
  89. GRB021104: optical observations
  90. Detection of activity from SGR 1900+14 with the RXTE/PCA
  91. IPN triangulation of GRB021027 (single large error box)
  92. IPN triangulation of GRB021027 (two large error boxes)
  93. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  94. GRB 021004: optical observations
  95. IPN triangulation of GRB021023 (small error boc)
  96. GRB 020813; likely host galaxy.
  97. IPN triangulation of GRB021020 (smaller error box)
  98. IPN triangulation of GRB021020
  99. GRB 021008, optical observations
  100. IPN triangulation of GRB021016 (small error box)

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