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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"

26370 results found.

  1. GRB 030228, optical observations
  2. GRB 030227: Confirmed Optical Afterglow (S1-A)
  3. GRB 030227: fading of candidate optical afterglow 'S1-A'
  4. GRB030227:Optical observations
  5. GRB 030227, possible optical counterpart of XMM-Newton source
  6. GRB030227 - faint tentative OT candidate
  7. GRB 030226, optical observations
  8. XMM-Newton observation of GRB030227
  9. GRB030227: Kiso optical observations
  10. GRB 030227: Kyoto optical observation
  11. GRB 030226, optical light curve
  12. GRB030227 localized by INTEGRAL
  13. GRB 030226 : Predicted light curve
  14. GRB030226: ESI spectroscopy
  15. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  16. GRB 030226 simultaneous optical observations
  17. GRB 030226, optical observations
  18. GRB030226: Optical decay index
  19. GRB 030226 Optical Spectra and R,I,z' Imaging
  20. GRB: Non-Referencing of GCN Circulars.
  21. IPN triangulation of GRB030217 (small error box)
  22. GRB 030131: marginal optical detection
  23. GRB 030204: Optical Observations
  24. GRB030204 field photometry
  25. GRB020819: Kiso R and I band observations
  26. GRB030131: Candidate Optical Afterglow
  27. IPN triangulation of GRB030204 (small error box)
  28. GRB 030131, optical observations
  29. GRB 030131: afterglow candidate
  30. GRB 030115, late-time optical observations
  31. GRB030131: corrected INTEGRAL position
  32. GRB 020819: Host galaxy at Radio Position
  33. IPN triangulation of GRB030131
  34. GRB 030131 optical observations
  35. GRB 030131 optical observations
  36. A long GRB detected by INTEGRAL
  37. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  38. GRB 030115, simultaneous observations by BOOTES-1
  39. GRB 030115: IR observations with IRSF/SIRIUS
  40. IPN triangulation of GRB030115C (large error box)
  41. GRB030115, afterglow candidate
  42. GRB 021211: R-band observations at late-time
  43. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  44. GRB 030115 : Possible IR counterpart
  45. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  46. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  47. GRB 030115: APO Optical Observations
  48. Information about where HETE will be pointing
  49. VLT spectroscopy of the probable host of GRB 021211
  50. IPN triangulation of GRB030101 (two large error boxes)
  51. GRB 021211: Probable Host and Underlying Supernova
  52. GRB 021112: Evidence for Another Dark Optical Afterglow
  53. GRB 021219: OSN optical observations
  54. GRB021219, optical observations
  55. GRB021219, optical observation by MASTER
  56. VLT spectra of GRB 021211 revisited
  57. GRB021219: a long GRB localized by INTEGRAL
  58. GRB021211: APO optical observations
  59. XRF 020903 : HST observations
  60. GRB 021201: Optical Observations
  61. GRB 021211: CTIO observations
  62. GRB021211, BVRI field photometry
  63. GRB021211: Optical observations in CrAO
  64. GRB 021211, optical observations
  65. GRB021211: Kiso Observations
  66. GRB 021201, optical observations
  67. GRB021211: Optical observations
  68. GRB 021201 (short/hard), NOT observations
  69. SUB-MM SEARCH FOR GRB 021211
  70. Chandra observation of the IPN error box of GRB021201 (short/hard)
  71. GRB 021211, R- and I-band observations
  72. GRB021211 - Upper limits from recent and historical observations
  73. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  74. IPN triangulation of GRB021206 (small error box)
  75. IPN triangulation of GRB021205 (large error box)
  76. GRB021201, BVRcIc field photometry
  77. GRB 021201: BOOTES simultaneous optical observations
  78. IPN triangulation of GRB021201 (short/hard burst, small error box)
  79. GRB021004, late time optical observations
  80. GRB021004 Chandra Observation
  81. IPN detection of continued SGR1900+14 activity
  82. Improved IPN error box for GRB021125
  83. IPN BURST POSITION
  84. IPN triangulation of GRB021125 (INTEGRAL BURST)
  85. GRB021125 : A long GRB localized by INTEGRAL
  86. IPN confirmation of the reactivation of SGR1900+14
  87. GRB021113, SPI ACS observation
  88. GRB 021112: Afterglow or Variable Star?
  89. GRB021113: optical observations at Bisei
  90. GRB 021113: Evidence for a Dark Optical Afterglow
  91. GRB021112, BVRI field photometry
  92. GRB 021112: Variable Source in R-band search
  93. GRB021112: Optical Observations
  94. IPN triangulation of GRB021113 (=H2449; annulus)
  95. GRB 021113: Optical observations
  96. GRB 021112: RAPTOR Observations
  97. GRB021113 (=H2449): A Long GRB Localized by HETE
  98. GRB021112 (=H2448): A Long GRB Localized by HETE
  99. GRB 021016: Optical Observations
  100. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE

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