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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"

24783 results found.

  1. GRB030323, optical observations
  2. GRB030324, BVRcIc field photometry
  3. GRB030323, BVRcIc field calibration
  4. IPN triangulation of GRB030320 (small error box)
  5. Possible GRB 030320 localized by INTEGRAL
  6. IPN triangulation of GRB030306 (single small error box - REVISED)
  7. IPN triangulation of GRB030306 (single small error box)
  8. IPN triangulation of GRB030306 (two small error boxes)
  9. GRB030226, BVRc observations
  10. Chandra detection of the X-ray afterglow of GRB 030226
  11. GRB030227: Kiso optical upper limit
  12. GRB030227, BVRcIc field photometry
  13. GRB030226, BVRcIc field calibration
  14. GRB 030228, optical observations
  15. GRB 030227: Confirmed Optical Afterglow (S1-A)
  16. GRB 030227: fading of candidate optical afterglow 'S1-A'
  17. GRB030227:Optical observations
  18. GRB 030227, possible optical counterpart of XMM-Newton source
  19. GRB030227 - faint tentative OT candidate
  20. GRB 030226, optical observations
  21. XMM-Newton observation of GRB030227
  22. GRB030227: Kiso optical observations
  23. GRB 030227: Kyoto optical observation
  24. GRB 030226, optical light curve
  25. GRB030227 localized by INTEGRAL
  26. GRB 030226 : Predicted light curve
  27. GRB030226: ESI spectroscopy
  28. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  29. GRB 030226 simultaneous optical observations
  30. GRB 030226, optical observations
  31. GRB030226: Optical decay index
  32. GRB 030226 Optical Spectra and R,I,z' Imaging
  33. GRB: Non-Referencing of GCN Circulars.
  34. IPN triangulation of GRB030217 (small error box)
  35. GRB 030131: marginal optical detection
  36. GRB 030204: Optical Observations
  37. GRB030204 field photometry
  38. GRB020819: Kiso R and I band observations
  39. GRB030131: Candidate Optical Afterglow
  40. IPN triangulation of GRB030204 (small error box)
  41. GRB 030131, optical observations
  42. GRB 030131: afterglow candidate
  43. GRB 030115, late-time optical observations
  44. GRB030131: corrected INTEGRAL position
  45. GRB 020819: Host galaxy at Radio Position
  46. IPN triangulation of GRB030131
  47. GRB 030131 optical observations
  48. GRB 030131 optical observations
  49. A long GRB detected by INTEGRAL
  50. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  51. GRB 030115, simultaneous observations by BOOTES-1
  52. GRB 030115: IR observations with IRSF/SIRIUS
  53. IPN triangulation of GRB030115C (large error box)
  54. GRB030115, afterglow candidate
  55. GRB 021211: R-band observations at late-time
  56. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  57. GRB 030115 : Possible IR counterpart
  58. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  59. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  60. GRB 030115: APO Optical Observations
  61. Information about where HETE will be pointing
  62. VLT spectroscopy of the probable host of GRB 021211
  63. IPN triangulation of GRB030101 (two large error boxes)
  64. GRB 021211: Probable Host and Underlying Supernova
  65. GRB 021112: Evidence for Another Dark Optical Afterglow
  66. GRB 021219: OSN optical observations
  67. GRB021219, optical observations
  68. GRB021219, optical observation by MASTER
  69. VLT spectra of GRB 021211 revisited
  70. GRB021219: a long GRB localized by INTEGRAL
  71. GRB021211: APO optical observations
  72. XRF 020903 : HST observations
  73. GRB 021201: Optical Observations
  74. GRB 021211: CTIO observations
  75. GRB021211, BVRI field photometry
  76. GRB021211: Optical observations in CrAO
  77. GRB 021211, optical observations
  78. GRB021211: Kiso Observations
  79. GRB 021201, optical observations
  80. GRB021211: Optical observations
  81. GRB 021201 (short/hard), NOT observations
  82. SUB-MM SEARCH FOR GRB 021211
  83. Chandra observation of the IPN error box of GRB021201 (short/hard)
  84. GRB 021211, R- and I-band observations
  85. GRB021211 - Upper limits from recent and historical observations
  86. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  87. IPN triangulation of GRB021206 (small error box)
  88. IPN triangulation of GRB021205 (large error box)
  89. GRB021201, BVRcIc field photometry
  90. GRB 021201: BOOTES simultaneous optical observations
  91. IPN triangulation of GRB021201 (short/hard burst, small error box)
  92. GRB021004, late time optical observations
  93. GRB021004 Chandra Observation
  94. IPN detection of continued SGR1900+14 activity
  95. Improved IPN error box for GRB021125
  96. IPN BURST POSITION
  97. IPN triangulation of GRB021125 (INTEGRAL BURST)
  98. GRB021125 : A long GRB localized by INTEGRAL
  99. IPN confirmation of the reactivation of SGR1900+14
  100. GRB021113, SPI ACS observation

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