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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"

28058 results found.

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

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