Follow UsSurvey of the Low-Redshift Intergalactic Medium with HST/COS
Danforth et al. (2016), ApJ, 817, 111
Example subsection of a spectrum for the IGM sightline 3C57. Features marked in red are intergalactic absorber lines from systems at various redshifts.
Introduction
A survey of the low-redshift intergalactic medium (IGM) has been performed by Danforth et al. (2015). Using HST COS spectra of 82 UV-bright AGN, several thousand absorption lines are identified from 2,610 distinct redshift systems at z < 0.723. The spectral features were selected and measured using a semi-automated analysis to minimize bias in line identification. For each of the 82 sightlines, a coadded, continuum-fitted spectrum is provided in FITS format (*_spec.fits). Two catalogs for each sightline are presented: one catalog lists the identified spectral features sorted by wavelength (*_linelist.txt files), while another lists the absorption features associated with IGM systems sorted by redshift (*_igm_systems.txt). Finally, preview plots of each sightline's spectrum are provided in PDF and PS format, complete with line identifications (*_atlas.pdf / *_atlas.ps). For convenience, we provide machine-readable versions of Table 1 and Table 2 from Danforth et al. 2015.
Note: this third version (v3) of the catalog replaces the 2014 version with a more accurate data reduction, higher S/N spectra, and a somewhat expanded list of sources. In addition, we include a "Galactic foreground" spectrum useful in identifying commonly-observed absorption features arising in the Galactic ISM. This spectrum is generated by median-combining the entire sample of 82 normalized spectra in observed wavelength. It is very high S/N and reveals the presence of many very weak absorption lines which may occasionally appear in spectra. You can download the Galactic foreground FITS, PS, and PDF files at the top of the target table.
FITS File Spectra - Data Format
The FITS headers and data format of the *_spec.fits files are summarized in this table (show / hide).
Quick-Look Plots - Data Format
An explanation of the quick-look plots' legends and data format (*_atlas.ps and *_atlas.pdf files) are summarized in this section (show / hide).
IGM Atlas, Plot Tool, and Data Download
Links provide access to download the spectrum (FITS file), visit interactive plot for that sightline, view the quick-look preview plots for the spectrum, and download the catalog of linelists or absorber systems for each sightline. To access the interactive plots, click on the "INT" link in the PLOTS column in the table.
Click here to bulk-download a gzipped tarball (110 MB) containing all files for every sight line. Click here for a machine-readable version of this table. Note that the flux column is the median continuum flux in units of 10-15 erg cm-2 s-1 Å-1.
| Galactic Foregound Model SPECTRUM (FITS) PLOTS: (INT) (PS) (PDF) |
| Sightline Name | Short Name | RA (deg) (J2000) |
DEC (J2000) |
AGN z (Redshift) |
Flux | AGN Type | SPECTRUM | LINELIST | SYSTEMS | PLOTS |
|---|---|---|---|---|---|---|---|---|---|---|
| 1ES1028+511 | 1es1028 | 157.8270833 | 50.893333 | 0.3604 | 2.6 | BLLac | FITS | TXT | TXT | INT PS PDF |
| 1ES1553+113 | 1es1553 | 238.9293500 | 11.190103 | 0.4140 | 15.9 | BLLac/FSRQ | FITS | TXT | TXT | INT PS PDF |
| 1SAXJ1032.3+5051 | 1sj1032 | 158.0670833 | 50.855556 | 0.1731 | 1.1 | AGN | FITS | TXT | TXT | INT PS PDF |
| 3C263 | 3c263 | 174.9874458 | 65.796997 | 0.6460 | 10.4 | FR2/Sy1.2 | FITS | TXT | TXT | INT PS PDF |
| 3C273 | 3c273 | 187.2778962 | 2.052406 | 0.1583 | 461.5 | FSRQ/Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| 3C57 | 3c57 | 30.4881667 | -11.542536 | 0.6705 | 6.6 | Sy1.2 | FITS | TXT | TXT | INT PS PDF |
| 3C66A | 3c66a | 35.6650500 | 43.035500 | 0.3347 | 6.8 | BLLac | FITS | TXT | TXT | INT PS PDF |
| B0117-2837 | b0117 | 19.8987358 | -28.358731 | 0.3489 | 11.6 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| FBQSJ1010+3003 | f1010 | 152.5029167 | 30.056111 | 0.2558 | 2.5 | QSO | FITS | TXT | TXT | INT PS PDF |
| H1821+643 | h1821 | 275.4887500 | 64.343333 | 0.2968 | 53.0 | Sy1.2 | FITS | TXT | TXT | INT PS PDF |
| H2356-309 | h2356 | 359.7830500 | -30.628031 | 0.1651 | 1.8 | BLLac | FITS | TXT | TXT | INT PS PDF |
| HE0056-3622 | he0056 | 14.6557779 | -36.101397 | 0.1641 | 17.3 | Sy1 | FITS | TXT | TXT | INT PS PDF |
| HE0153-4520 | he0153 | 28.8050000 | -45.103333 | 0.4510 | 15.8 | QSO | FITS | TXT | TXT | INT PS PDF |
| HE0226-4110 | he0226 | 37.0633004 | -40.954058 | 0.4934 | 21.4 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| HE0238-1904 | he0238 | 40.1354167 | -18.864167 | 0.6310 | 14.0 | QSO | FITS | TXT | TXT | INT PS PDF |
| HE0435-5304 | he0435 | 69.2116667 | -52.980278 | 0.4300 | 2.5 | QSO | FITS | TXT | TXT | INT PS PDF |
| HS1102+3441 | hs1102 | 166.4158254 | 34.426222 | 0.5088 | 3.6 | QSO | FITS | TXT | TXT | INT PS PDF |
| IRASF22456-5125 | i22456 | 342.1716850 | -51.164764 | 0.1000 | 19.3 | Sy1.5 | FITS | TXT | TXT | INT PS PDF |
| IRASL06229-6434 | i06229 | 95.7820000 | -64.605750 | 0.1290 | 8.0 | FSRQ | FITS | TXT | TXT | INT PS PDF |
| MR2251-178 | mr2251 | 343.5245000 | -17.582028 | 0.0640 | 34.3 | Sy1.5 | FITS | TXT | TXT | INT PS PDF |
| MRK106 | mrk106 | 139.9806683 | 55.360397 | 0.1230 | 11.4 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| MRK1513 | mrk1513 | 323.1163333 | 10.138528 | 0.0630 | 17.5 | Sy1.5 | FITS | TXT | TXT | INT PS PDF |
| MRK478 | mrk478 | 220.5311250 | 35.439722 | 0.0791 | 26.4 | NLSy1 | FITS | TXT | TXT | INT PS PDF |
| MRK876 | mrk876 | 243.4883333 | 65.719444 | 0.1290 | 39.5 | Sy1 | FITS | TXT | TXT | INT PS PDF |
| PG0003+158 | pg0003 | 1.4968167 | 16.163614 | 0.4509 | 7.7 | Sy1.2 | FITS | TXT | TXT | INT PS PDF |
| PG0026+129 | pg0026 | 7.3071250 | 13.267778 | 0.1420 | 19.1 | Sy1 | FITS | TXT | TXT | INT PS PDF |
| PG0157+001 | pg0157 | 29.9593750 | 0.394806 | 0.1631 | 20.4 | Sy1.5 | FITS | TXT | TXT | INT PS PDF |
| PG0804+761 | pg0804 | 122.7441963 | 76.044894 | 0.1000 | 79.6 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| PG0832+251 | pg0832 | 128.8991667 | 24.994722 | 0.3298 | 3.5 | QSO | FITS | TXT | TXT | INT PS PDF |
| PG0838+770 | pg0838 | 131.1885833 | 76.885972 | 0.1310 | 8.5 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| PG0844+349 | pg0844 | 131.9268750 | 34.751222 | 0.0640 | 25.5 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| PG0953+414 | pg0953 | 149.2183750 | 41.256139 | 0.2341 | 38.1 | QSO | FITS | TXT | TXT | INT PS PDF |
| PG1001+291 | pg1001 | 151.0107771 | 28.926439 | 0.3297 | 10.6 | Sy1 | FITS | TXT | TXT | INT PS PDF |
| PG1011-040 | pg1011 | 153.5861667 | -4.311244 | 0.0583 | 16.2 | Sy1.2 | FITS | TXT | TXT | INT PS PDF |
| PG1048+342 | pg1048 | 162.9329000 | 33.990750 | 0.1671 | 5.9 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| PG1049-005 | pg1049 | 162.9645000 | -0.854900 | 0.3599 | 9.2 | Sy1.5 | FITS | TXT | TXT | INT PS PDF |
| PG1115+407 | pg1115 | 169.6262500 | 40.431667 | 0.1546 | 10.5 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| PG1116+215 | pg1116 | 169.7858333 | 21.321667 | 0.1763 | 45.7 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| PG1121+422 | pg1121 | 171.1632667 | 42.029172 | 0.2250 | 7.4 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| PG1216+069 | pg1216 | 184.8372167 | 6.644033 | 0.3313 | 12.3 | NLSy1 | FITS | TXT | TXT | INT PS PDF |
| PG1222+216 | pg1222 | 186.2268675 | 21.379539 | 0.4320 | 17.0 | Blazar | FITS | TXT | TXT | INT PS PDF |
| PG1229+204 | pg1229 | 188.0150417 | 20.158167 | 0.0630 | 19.2 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| PG1259+593 | pg1259 | 195.3037500 | 59.035278 | 0.4778 | 15.3 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| PG1307+085 | pg1307 | 197.4458750 | 8.330083 | 0.1550 | 25.0 | Sy1.2 | FITS | TXT | TXT | INT PS PDF |
| PG1309+355 | pg1309 | 198.0739583 | 35.255861 | 0.1829 | 10.1 | QSO | FITS | TXT | TXT | INT PS PDF |
| PG1424+240 | pg1424 | 216.7516325 | 23.800011 | 0.6035 | 15.2 | BLLac | FITS | TXT | TXT | INT PS PDF |
| PG1435-067 | pg1435 | 219.5672917 | -6.972417 | 0.1260 | 16.2 | QSO | FITS | TXT | TXT | INT PS PDF |
| PG1626+554 | pg1626 | 246.9838333 | 55.375419 | 0.1330 | 22.8 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| PG2349-014 | pg2349 | 357.9838333 | -1.153639 | 0.1737 | 29.8 | Sy1.2 | FITS | TXT | TXT | INT PS PDF |
| PHL1811 | phl1811 | 328.7562500 | -9.373611 | 0.1920 | 56.2 | NLSy1 | FITS | TXT | TXT | INT PS PDF |
| PHL2525 | phl2525 | 0.1017646 | -12.763267 | 0.1990 | 17.7 | QSO | FITS | TXT | TXT | INT PS PDF |
| PKS0405-123 | pks0405 | 61.9517954 | -12.193517 | 0.5740 | 32.1 | Sy1.2 | FITS | TXT | TXT | INT PS PDF |
| PKS0552-640 | pks0552 | 88.1020833 | -64.036333 | 0.6800 | 11.1 | AGN | FITS | TXT | TXT | INT PS PDF |
| PKS0558-504 | pks0558 | 89.9474583 | -50.447750 | 0.1372 | 28.1 | NLSy1/FSRQ | FITS | TXT | TXT | INT PS PDF |
| PKS0637-752 | pks0637 | 98.9437500 | -75.271336 | 0.6500 | 8.0 | FSRQ | FITS | TXT | TXT | INT PS PDF |
| PKS1302-102 | pks1302 | 196.3875000 | -10.555278 | 0.2784 | 14.9 | FSRQ/Sy1.2 | FITS | TXT | TXT | INT PS PDF |
| PKS2005-489 | pks2005 | 302.3557942 | -48.831589 | 0.0710 | 22.3 | BLLac | FITS | TXT | TXT | INT PS PDF |
| PKS2155-304 | pks2155 | 329.7169379 | -30.225589 | 0.1165 | 73.1 | BLLac | FITS | TXT | TXT | INT PS PDF |
| PMNJ1103-2329 | p1103 | 165.9066667 | -23.491667 | 0.1860 | 2.1 | BLLac/FSRQ | FITS | TXT | TXT | INT PS PDF |
| PMNJ2345-1555 | pmn2345 | 356.3019263 | -15.918842 | 0.6210 | 7.0 | FSRQ | FITS | TXT | TXT | INT PS PDF |
| Q1230+0115 | q1230 | 187.7083508 | 1.255972 | 0.1170 | 36.3 | NLSy1 | FITS | TXT | TXT | INT PS PDF |
| QSO0045+3926 | q0045 | 12.0790833 | 39.686556 | 0.1340 | 9.3 | Sy1 | FITS | TXT | TXT | INT PS PDF |
| RBS144 | rbs144 | 15.1130458 | -51.231803 | 0.0628 | 22.1 | Sy1 | FITS | TXT | TXT | INT PS PDF |
| RBS1892 | rbs1892 | 341.3346225 | -46.869944 | 0.2000 | 20.3 | Sy1 | FITS | TXT | TXT | INT PS PDF |
| RBS542 | rbs542 | 66.5029167 | -57.200500 | 0.1040 | 33.1 | Sy1.5 | FITS | TXT | TXT | INT PS PDF |
| RXJ0439.6-5311 | rxj0439 | 69.9110146 | -53.192100 | 0.2430 | 3.5 | Sy1 | FITS | TXT | TXT | INT PS PDF |
| RXJ0503.1-6634 | rxj0503 | 75.7663750 | -66.562750 | 0.0640 | 6.4 | Sy1 | FITS | TXT | TXT | INT PS PDF |
| RXJ2154.1-4414 | rxj2154 | 328.7127688 | -44.235000 | 0.3440 | 9.8 | Sy1 | FITS | TXT | TXT | INT PS PDF |
| RXSJ09565-0452 | rxj0956 | 149.1257500 | -4.888056 | 0.1550 | 4.6 | Sy1 | FITS | TXT | TXT | INT PS PDF |
| S50716+714 | s50716 | 110.4727017 | 71.343433 | 0.2315 | 24.3 | BLLac | FITS | TXT | TXT | INT PS PDF |
| SBS1108+560 | sbs1108 | 167.8841667 | 55.790556 | 0.7666 | 4.9 | QSO | FITS | TXT | TXT | INT PS PDF |
| SBS1122+594 | sbs1122 | 171.4741250 | 59.172667 | 0.8520 | 2.7 | QSO | FITS | TXT | TXT | INT PS PDF |
| SDSSJ080908.13+461925 | s080908 | 122.2839000 | 46.323800 | 0.6563 | 7.2 | QSO | FITS | TXT | TXT | INT PS PDF |
| SDSSJ092554.43+453544 | s09255b | 141.4768500 | 45.595700 | 0.3295 | 5.1 | QSO | FITS | TXT | TXT | INT PS PDF |
| SDSSJ092909.79+464424 | s092909 | 142.2907500 | 46.740000 | 0.2400 | 11.5 | QSO | FITS | TXT | TXT | INT PS PDF |
| SDSSJ094952.91+390203 | s094952 | 147.4705500 | 39.034400 | 0.3656 | 7.8 | QSO | FITS | TXT | TXT | INT PS PDF |
| SDSSJ135712.61+170444 | s135712 | 209.3025000 | 17.078900 | 0.1500 | 4.7 | QSO | FITS | TXT | TXT | INT PS PDF |
| TON1187 | ton1187 | 153.2633333 | 35.856389 | 0.0789 | 17.3 | Sy1.2 | FITS | TXT | TXT | INT PS PDF |
| TON236 | ton236 | 232.1691746 | 28.424928 | 0.4500 | 6.1 | Sy1.2 | FITS | TXT | TXT | INT PS PDF |
| TON580 | ton580 | 172.7895833 | 31.234722 | 0.2902 | 9.5 | Sy1.0/FSRQ? | FITS | TXT | TXT | INT PS PDF |
| TONS210 | tons210 | 20.4646250 | -28.349389 | 0.1160 | 35.9 | Sy1.0 | FITS | TXT | TXT | INT PS PDF |
| UKS0242-724 | uks0242 | 40.7900000 | -72.280111 | 0.1018 | 10.3 | Sy1.2 | FITS | TXT | TXT | INT PS PDF |
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