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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"

25073 results found.

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

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