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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"

28082 results found.

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

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