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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"

27393 results found.

  1. GRB030324 optical observation
  2. GRB030131, BVRcIc field photometry
  3. Possible GRB030323 localized by INTEGRAL
  4. GRB030323: Detection on 2003/03/24
  5. IPN triangulation of GRB030326 (single small error box)
  6. IPN triangulation of GRB030325 (two small error boxes)
  7. GRB030323: V, R, I photometry
  8. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  9. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  10. VLT/FORS2 spectra of GRB 030323
  11. GRB030323, optical observations
  12. GRB030324, BVRcIc field photometry
  13. GRB030323, BVRcIc field calibration
  14. IPN triangulation of GRB030320 (small error box)
  15. Possible GRB 030320 localized by INTEGRAL
  16. IPN triangulation of GRB030306 (single small error box - REVISED)
  17. IPN triangulation of GRB030306 (single small error box)
  18. IPN triangulation of GRB030306 (two small error boxes)
  19. GRB030226, BVRc observations
  20. Chandra detection of the X-ray afterglow of GRB 030226
  21. GRB030227: Kiso optical upper limit
  22. GRB030227, BVRcIc field photometry
  23. GRB030226, BVRcIc field calibration
  24. GRB 030228, optical observations
  25. GRB 030227: Confirmed Optical Afterglow (S1-A)
  26. GRB 030227: fading of candidate optical afterglow 'S1-A'
  27. GRB030227:Optical observations
  28. GRB 030227, possible optical counterpart of XMM-Newton source
  29. GRB030227 - faint tentative OT candidate
  30. GRB 030226, optical observations
  31. XMM-Newton observation of GRB030227
  32. GRB030227: Kiso optical observations
  33. GRB 030227: Kyoto optical observation
  34. GRB 030226, optical light curve
  35. GRB030227 localized by INTEGRAL
  36. GRB 030226 : Predicted light curve
  37. GRB030226: ESI spectroscopy
  38. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  39. GRB 030226 simultaneous optical observations
  40. GRB 030226, optical observations
  41. GRB030226: Optical decay index
  42. GRB 030226 Optical Spectra and R,I,z' Imaging
  43. GRB: Non-Referencing of GCN Circulars.
  44. IPN triangulation of GRB030217 (small error box)
  45. GRB 030131: marginal optical detection
  46. GRB 030204: Optical Observations
  47. GRB030204 field photometry
  48. GRB020819: Kiso R and I band observations
  49. GRB030131: Candidate Optical Afterglow
  50. IPN triangulation of GRB030204 (small error box)
  51. GRB 030131, optical observations
  52. GRB 030131: afterglow candidate
  53. GRB 030115, late-time optical observations
  54. GRB030131: corrected INTEGRAL position
  55. GRB 020819: Host galaxy at Radio Position
  56. IPN triangulation of GRB030131
  57. GRB 030131 optical observations
  58. GRB 030131 optical observations
  59. A long GRB detected by INTEGRAL
  60. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  61. GRB 030115, simultaneous observations by BOOTES-1
  62. GRB 030115: IR observations with IRSF/SIRIUS
  63. IPN triangulation of GRB030115C (large error box)
  64. GRB030115, afterglow candidate
  65. GRB 021211: R-band observations at late-time
  66. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  67. GRB 030115 : Possible IR counterpart
  68. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  69. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  70. GRB 030115: APO Optical Observations
  71. Information about where HETE will be pointing
  72. VLT spectroscopy of the probable host of GRB 021211
  73. IPN triangulation of GRB030101 (two large error boxes)
  74. GRB 021211: Probable Host and Underlying Supernova
  75. GRB 021112: Evidence for Another Dark Optical Afterglow
  76. GRB 021219: OSN optical observations
  77. GRB021219, optical observations
  78. GRB021219, optical observation by MASTER
  79. VLT spectra of GRB 021211 revisited
  80. GRB021219: a long GRB localized by INTEGRAL
  81. GRB021211: APO optical observations
  82. XRF 020903 : HST observations
  83. GRB 021201: Optical Observations
  84. GRB 021211: CTIO observations
  85. GRB021211, BVRI field photometry
  86. GRB021211: Optical observations in CrAO
  87. GRB 021211, optical observations
  88. GRB021211: Kiso Observations
  89. GRB 021201, optical observations
  90. GRB021211: Optical observations
  91. GRB 021201 (short/hard), NOT observations
  92. SUB-MM SEARCH FOR GRB 021211
  93. Chandra observation of the IPN error box of GRB021201 (short/hard)
  94. GRB 021211, R- and I-band observations
  95. GRB021211 - Upper limits from recent and historical observations
  96. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  97. IPN triangulation of GRB021206 (small error box)
  98. IPN triangulation of GRB021205 (large error box)
  99. GRB021201, BVRcIc field photometry
  100. GRB 021201: BOOTES simultaneous optical observations

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