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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"

39167 results found.

  1. GRB 990510: Broad Band Break
  2. GRB 990510: BATSE Observations
  3. GRB 990510 Optical Observations
  4. GRB 990510, BVI photometry
  5. GRB 990510 optical observations
  6. GRB 990510: BeppoSAX/GRBM observations
  7. GRB990510 optical observations
  8. GRB 990510 optical observations
  9. GRB 990510 optical observations
  10. Galactic extinction towards GRB 990510
  11. GRB 990510 optical observations
  12. IPN localization of GRB990510
  13. GRB 990506 Radio Observations
  14. GRB 990123, optical monitoring
  15. GRB 990506: BATSE Observations
  16. GRB 990506, optical observations
  17. GRB 990510: Final BeppoSAX-WFC Coordinates
  18. GRB 990506, Optical Observations
  19. GRB 990506 optical observations
  20. GRB 990506 optical observations
  21. GRB 990506, optical observations
  22. GRB990506 observation plan
  23. Refined IPN error box for GRB990506
  24. GRB 990506: Limits on the possible optical transient
  25. GRB 990506, armchair astronomy
  26. GRB 990506, optical observations from +1 to +3 hours
  27. GRB 990506, optical observations
  28. GRB990506 observation plan
  29. New IPN/RXTE error box for GRB990506
  30. IPN localization for GRB990506
  31. GRB 970228: Redshift and properties of the host galaxy
  32. IPN localization of GRB990427
  33. GRB981220 VLBA observations
  34. GRB990321 REFINED IPN ANNULUS
  35. GRB990323 PRECISE IPN POSITION
  36. GRB990321 IPN TRIANGULATION
  37. GRB 990316 Optical Observations
  38. GRB 990316, Radio observations
  39. GRB 990316, Optical observations
  40. GRB990316, Optical observations
  41. GRB 990316 optical observations
  42. GRB990316: simultaneous optical observation
  43. ASM/IPN error box for GRB 990308 (BATSE #7457)
  44. GRB990308 not a new SGR
  45. GRB 990308a and GRB 990308b
  46. GRB990308 (Trig. 7457), optical observations
  47. GRB981220, IPN localization
  48. GRB 981220, radio observations
  49. GRB 990123, Field Photometry
  50. GRB 990217 Optical Observations
  51. GRB 990217, radio observations
  52. Optical Observations of GRB990217
  53. GRB990123: Caltech STIS Photometry and Images
  54. GRB990123 observations
  55. GRB990123, Optical Observation
  56. GRB 990123: Discovery of the Probable Host Galaxy
  57. GRB 990123: Reduced HST Images
  58. For Immediate Posting to GCN - HST Data GRB 990123 Available
  59. GRB19990123 observations
  60. GRB 990123: BVRI standards in the field
  61. GRB 990123: Updated Keck Spectroscopy Results
  62. GRB981220, field photometry
  63. GRB 990123 NOT Spectrum Update
  64. GRB990123, Optical observation
  65. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  66. GRB 990123: Publicly available reduced HST images
  67. GRB990123, Upcoming HST Service Observations
  68. GRB 990123: New Constraints on Possible Foreground Galaxies
  69. GRB990123 Optical Observations
  70. GRB990123, Probability of gravitational lensing
  71. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  72. GRB 990123: Continued Radio Observations
  73. GRB990123, Preliminary Lens Search Results
  74. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  75. On the Lensing Interpretation of GRB 990123
  76. Search for Potential Images of GRB 990123
  77. Search for Potential Images of GRB 990123
  78. GRB990123, Optical BVRI Observations
  79. GRB 990123: near-infrared observations.
  80. GRB990123, OSSE observations
  81. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  82. "GRB 990123: New BV Observations"
  83. GRB 990123 Optical Follow-Up
  84. GRB 990123; Addendum to GCN 223
  85. GRB 990123: BATSE Observations
  86. GRB 990123 Keck Spectrum update
  87. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  88. GRB990123 Optical Observations
  89. GRB 990123 Spectroscopic Redshifts
  90. GRB 990123: New Optical Observations, Decay Measure
  91. GRB 990123 Optical Follow-Up
  92. GRB 990123: Possible Gravitationally Lensed Burst?
  93. GRB 990123 optical observations
  94. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  95. GRB 990123 radio observations
  96. GRB 990123, new radio source
  97. GRB990123, Optical observation
  98. GRB 990123: Optical Decay Slope
  99. GRB 990123 r-band photometry
  100. GRB 990123 Optical Follow-up

Advanced

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