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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"

24881 results found.

  1. GRB030323, BVRcIc field calibration
  2. IPN triangulation of GRB030320 (small error box)
  3. Possible GRB 030320 localized by INTEGRAL
  4. IPN triangulation of GRB030306 (single small error box - REVISED)
  5. IPN triangulation of GRB030306 (single small error box)
  6. IPN triangulation of GRB030306 (two small error boxes)
  7. GRB030226, BVRc observations
  8. Chandra detection of the X-ray afterglow of GRB 030226
  9. GRB030227: Kiso optical upper limit
  10. GRB030227, BVRcIc field photometry
  11. GRB030226, BVRcIc field calibration
  12. GRB 030228, optical observations
  13. GRB 030227: Confirmed Optical Afterglow (S1-A)
  14. GRB 030227: fading of candidate optical afterglow 'S1-A'
  15. GRB030227:Optical observations
  16. GRB 030227, possible optical counterpart of XMM-Newton source
  17. GRB030227 - faint tentative OT candidate
  18. GRB 030226, optical observations
  19. XMM-Newton observation of GRB030227
  20. GRB030227: Kiso optical observations
  21. GRB 030227: Kyoto optical observation
  22. GRB 030226, optical light curve
  23. GRB030227 localized by INTEGRAL
  24. GRB 030226 : Predicted light curve
  25. GRB030226: ESI spectroscopy
  26. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  27. GRB 030226 simultaneous optical observations
  28. GRB 030226, optical observations
  29. GRB030226: Optical decay index
  30. GRB 030226 Optical Spectra and R,I,z' Imaging
  31. GRB: Non-Referencing of GCN Circulars.
  32. IPN triangulation of GRB030217 (small error box)
  33. GRB 030131: marginal optical detection
  34. GRB 030204: Optical Observations
  35. GRB030204 field photometry
  36. GRB020819: Kiso R and I band observations
  37. GRB030131: Candidate Optical Afterglow
  38. IPN triangulation of GRB030204 (small error box)
  39. GRB 030131, optical observations
  40. GRB 030131: afterglow candidate
  41. GRB 030115, late-time optical observations
  42. GRB030131: corrected INTEGRAL position
  43. GRB 020819: Host galaxy at Radio Position
  44. IPN triangulation of GRB030131
  45. GRB 030131 optical observations
  46. GRB 030131 optical observations
  47. A long GRB detected by INTEGRAL
  48. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  49. GRB 030115, simultaneous observations by BOOTES-1
  50. GRB 030115: IR observations with IRSF/SIRIUS
  51. IPN triangulation of GRB030115C (large error box)
  52. GRB030115, afterglow candidate
  53. GRB 021211: R-band observations at late-time
  54. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  55. GRB 030115 : Possible IR counterpart
  56. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  57. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  58. GRB 030115: APO Optical Observations
  59. Information about where HETE will be pointing
  60. VLT spectroscopy of the probable host of GRB 021211
  61. IPN triangulation of GRB030101 (two large error boxes)
  62. GRB 021211: Probable Host and Underlying Supernova
  63. GRB 021112: Evidence for Another Dark Optical Afterglow
  64. GRB 021219: OSN optical observations
  65. GRB021219, optical observations
  66. GRB021219, optical observation by MASTER
  67. VLT spectra of GRB 021211 revisited
  68. GRB021219: a long GRB localized by INTEGRAL
  69. GRB021211: APO optical observations
  70. XRF 020903 : HST observations
  71. GRB 021201: Optical Observations
  72. GRB 021211: CTIO observations
  73. GRB021211, BVRI field photometry
  74. GRB021211: Optical observations in CrAO
  75. GRB 021211, optical observations
  76. GRB021211: Kiso Observations
  77. GRB 021201, optical observations
  78. GRB021211: Optical observations
  79. GRB 021201 (short/hard), NOT observations
  80. SUB-MM SEARCH FOR GRB 021211
  81. Chandra observation of the IPN error box of GRB021201 (short/hard)
  82. GRB 021211, R- and I-band observations
  83. GRB021211 - Upper limits from recent and historical observations
  84. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  85. IPN triangulation of GRB021206 (small error box)
  86. IPN triangulation of GRB021205 (large error box)
  87. GRB021201, BVRcIc field photometry
  88. GRB 021201: BOOTES simultaneous optical observations
  89. IPN triangulation of GRB021201 (short/hard burst, small error box)
  90. GRB021004, late time optical observations
  91. GRB021004 Chandra Observation
  92. IPN detection of continued SGR1900+14 activity
  93. Improved IPN error box for GRB021125
  94. IPN BURST POSITION
  95. IPN triangulation of GRB021125 (INTEGRAL BURST)
  96. GRB021125 : A long GRB localized by INTEGRAL
  97. IPN confirmation of the reactivation of SGR1900+14
  98. GRB021113, SPI ACS observation
  99. GRB 021112: Afterglow or Variable Star?
  100. GRB021113: optical observations at Bisei

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