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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. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  2. IPN/HETE summary of recent bursts from SGR1806-20
  3. XRF 030723: Detection of a rebrightening in the optical afterglow
  4. GRB030725: Optical observations
  5. XRF030723, BVRcIc field photometry update
  6. IPN triangulation of GRB030801 (large error box)
  7. GRB021206 optical counterpart upper limit
  8. IPN triangulation of GRB030731 (annulus)
  9. IBAS GRB Alerts 1011-1017 NOT CONFIRMED
  10. XRF030723: Re-analysis of ROTSE-III early images
  11. IPN triangulation of GRB030725 (=H2779; small error box)
  12. XRF030723 (=H2777): Second Epoch Magellan Observations
  13. GRB 030725: optical observations.
  14. GRB030725, optical transient observations
  15. IPN triangulation of GRB030726 (large error box)
  16. IPN triangulation of GRB030722 (large error box)
  17. IPN triangulation of GRB030721 (large error box)
  18. XRF030723 Radio Observations
  19. XRF 030723: confirmation of fading optical counterpart
  20. XRF030723(=H2777): Chandra Observations
  21. XRF 030723: VLT spectra
  22. Magellan Observations of XRF030723 (=H2777)
  23. GRB030723: Upper limits from historical observations
  24. GRB030725, possible optical transient
  25. XRF030723: Palomar observations and proposed counterpart
  26. GRB030725 (=H2779): A Bright GRB Localized by HETE
  27. XRF030723: optical observations
  28. XRF030723 (= H2777): Chandra Observations Scheduled
  29. XRF030723, BVRcIc field photometry correction
  30. XRF030723, ROTSE-III Early Observations
  31. XRF030723, BVRcIc field photometry
  32. XRF 030723, optical observations
  33. XRF030723, optical observations
  34. XRF 030723, optical observations
  35. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  36. GRB030723, optical observations
  37. Konus-Wind detection of the bursts from SGR1806-20 region
  38. IBAS GRB Alerts 969 970
  39. SGR 1806-20, submm observations
  40. H2768, H2770, and H2771: Three Bursts from SGR1806-20
  41. IPN triangulation of GRB030717 (annulus)
  42. RXTE PCA Observations of SGR1806-20 Region
  43. GRB030329: Subaru Optical Spectroscopy
  44. Triangulation of GRB030715 (single large error box)
  45. Triangulation of GRB030714 (single large error box)
  46. 030716 NOT a GRB
  47. IPN triangulation of GRB030714 (two large error boxes)
  48. IPN triangulation of GRB030715 (two large error boxes)
  49. GRB030329: RTT150 optical observations
  50. GRBlog: Compilation of all GCN Circ. data
  51. IPN detection of renewed activity from SGR1806-20
  52. IPN triangulation of GRB030711 (annulus, =SGR0525-66?)
  53. IPN triangulation of GRB030710 (annulus)
  54. IPN triangulation of GRB030709 (annulus)
  55. GRB030706 triangulation (single large error box)
  56. IPN triangulation of GRB030706 (annulus)
  57. IPN triangulation of GRB030629 (annulus)
  58. GRB030629 triangulation (Konus-Wind -- Helicon annulus)
  59. 030629 NOT a real GRB
  60. GRB030329, optical observation in May
  61. IPN triangulation of GRB030626 (single large error box)
  62. IPN triangulation of GRB030626 (two large error boxes)
  63. GRB030329: second XMM-Newton observation
  64. GRB030418: R optical observations
  65. HETE detection of burst from SGR1806-20
  66. GRB030329 -- RATAN-600 data in April-May
  67. Final IPN error ellipse for GRB021206 (the polarized GRB)
  68. GRB 021206, Radio afterglow candidate
  69. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  70. IPN triangulation of GRB030607 (annulus)
  71. IPN triangulation of GRB030606 (two alternate error boxes)
  72. GRB030329, SPM optical observations (Correction of GCN2075 R band)
  73. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  74. IPN triangulation of GRB030605B (annulus)
  75. GRB 030528: Optical Observations
  76. IPN triangulation of GRB030605 (annulus)
  77. GRB 030528: tentative NIR counterpart
  78. GRB 030528, radio observations
  79. GRB030528(=H2724): Observations with the Chandra X-ray Observatory
  80. GRB030329, further radio observations at GMRT
  81. GRB030528, BVRI field photometry
  82. IPN triangulation of GRB030601 (annulus)
  83. GRB030329, SPM optical observations
  84. GRB030528: Chandra TOO Planned
  85. GRB 030519B: optical observations.
  86. MASTER: optical observation GRB030601
  87. GRB030528(=H2724): Revised SXC Localization
  88. GRB 030329: optical observations
  89. GRB 030329/SN 2003dh: Jitter Episode
  90. GRB 030528, Teramo optical observation
  91. GRB 030528 Bisei optical observation
  92. GRB030528 (H2724): A long GRB localized by HETE
  93. GRB 030329: Correction to GCN 2254
  94. GRB 030329: Optical Observations
  95. GRB 030528: Optical observations at RIKEN
  96. GRB 030528 (=H2724) Kyoto optical observation
  97. IPN triangulation of GRB030523B (annulus)
  98. GRB 030416: Optical Observations
  99. GRB 030329: Planned XMM-Newton Observation
  100. IPN triangulation of GRB030523 (annulus)

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