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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').
  1. IPN triangulation of GRB030115B (annulus)
  2. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  3. Distribution of INTEGRAL SPI-ACS triggers
  4. GRB030115: R-band observations at Asiago
  5. GRB030115: TAROT optical observations
  6. GRB 021211: VLT spectrum
  7. GRB 030115: APO Optical Observations
  8. GRB 030115, no optical candidate
  9. GRB 030115, optical observations
  10. GRB 030115, optical candidate
  11. Possible GRB030113 seen by SPI ACS
  12. Probable GRB030112B seen by SPI ACS
  13. Probable GRB030112 seen by SPI ACS
  14. Information about where HETE will be pointing
  15. Possible GRB030111 seen by SPI ACS
  16. Possible GRB030110b seen by SPI ACS
  17. Possible GRB 030110 seen by SPI ACS
  18. IPN triangulation of GRB030109 (annulus)
  19. IPN triangulation of GRB030105 (large error box)
  20. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  21. Possible GRB 20030109 seen by SPI ACS
  22. IPN triangulation of GRB030102A - correction to peak flux
  23. IPN triangulation of GRB030102B (portion of annulus)
  24. IPN triangulation of GRB030102A (large error box)
  25. Coronas-F -Wind triangulation of GRB030102
  26. Possible GRB20030107 seen by SPI-ACS
  27. Possible GRB 20030105 seen by SPI ACS
  28. IPN triangulation of GRB030102 (annulus)
  29. GRB on 20030102 seen by SPI-ACS
  30. VLT spectroscopy of the probable host of GRB 021211
  31. GRB on 20030101 seen by SPI-ACS
  32. IPN triangulation of GRB030101 (two large error boxes)
  33. GRB021226
  34. GRB 021211: Probable Host and Underlying Supernova
  35. GRB 021226 registration by Helicon/Coronas-F
  36. Probable GRB in INTEGRAL SPI-ACS
  37. IPN triangulation of GRB021223 (two large error boxes)
  38. GRB021211, radio observations
  39. GRB 021112: Evidence for Another Dark Optical Afterglow
  40. GRB 021219: OSN optical observations
  41. GRB021219: Radio Observations
  42. GRB021219, optical observations
  43. IPN triangulation of GRB021219 - CORRECTION
  44. IPN triangulation of GRB021219
  45. GRB021219, optical observation by MASTER
  46. GRB021219: Correction to GCN 1766
  47. GRB021219 refined position with INTEGRAL
  48. VLT spectra of GRB 021211 revisited
  49. GRB021219: a long GRB localized by INTEGRAL
  50. GRB021211: APO optical observations
  51. IPN detection of continued activity from SGR1806-20
  52. IPN triangulation of GRB021215 (large error box)
  53. IPN triangulation of GRB021214 (annulus)
  54. XRF 020903 : HST observations
  55. GRB 021201: Optical Observations
  56. GRB 021211, optical observations
  57. GRB 021211: CTIO observations
  58. GRB021211: Measurement of Early Time Afterglow
  59. VLT spectrum of GRB 021211
  60. IPN triangulation of GRB021211B (two large error boxes)
  61. GRB 021211: early break in light curve
  62. GRB021211, BVRI field photometry
  63. GRB021211: Optical observations in CrAO
  64. GRB 021211, IR observations
  65. GRB 021211, optical observations
  66. GRB 021211: Optical Observations
  67. GRB021211: Kiso Observations
  68. GRB021204: Kiso Observations
  69. GRB 021201, optical observations
  70. GRB 021211: Radio Observations
  71. GRB021211: Optical observations
  72. GRB 021201 (short/hard), NOT observations
  73. SUB-MM SEARCH FOR GRB 021211
  74. Chandra observation of the IPN error box of GRB021201 (short/hard)
  75. GRB 021211 Milagro GeV/TeV Observations
  76. GRB 021211, R- and I-band observations
  77. GRB021211 - Upper limits from recent and historical observations
  78. GRB021211, OT at 108 s
  79. GRB021211 (HETE2493), OT at 143 sec
  80. GRB 021204: I-band Observations
  81. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  82. HETE 2493: Optical observations
  83. HETE 2493: Optical observations
  84. HETE 2493: Optical candidate
  85. GRB 021204: Optical Observations at RIKEN
  86. GRB 021125: Radio Observations
  87. IPN triangulation of GRB021206 (small error box)
  88. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  89. IPN detection of renewed activity from SGR1806-20
  90. IPN triangulation of GRB021205 (large error box)
  91. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  92. GRB021201, BVRcIc field photometry
  93. GRB 021201, Radio Observations
  94. GRB 021201: Optical Observations
  95. GRB 021201: BOOTES simultaneous optical observations
  96. IPN triangulation of GRB021201 (short/hard burst, small error box)
  97. Radio Catalog of GRB Afterglows
  98. GRB021004, late time optical observations
  99. GRB021004 Chandra Observation
  100. IPN detection of continued SGR1900+14 activity

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