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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"

25871 results found.

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

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