{"id":"7d2086ba-6cfe-4fbd-9be3-fb008ff48cf4","arxiv_id":"2505.11598","paper_version":2,"verdict":"CONDITIONAL","confidence":"HIGH","novelty_score":5.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":3,"one_line_summary":"A pipeline that converts PTA source parameter posteriors into host galaxy apparent magnitudes, and forecasts that WISE and SuperCOSMOS will cover most PTA host galaxies at z<0.4, while 2MASS becomes incomplete above 10^9.8 solar masses beyond 1 Gpc.","lead":"This paper shows how to turn the parameters a pulsar timing array measures from a supermassive black hole binary gravitational wave signal into predicted brightnesses of the host galaxy, using empirical galaxy scaling relations. It then compares those predictions with existing all-sky surveys to see how many host galaxies will actually be findable, concluding that WISE and SuperCOSMOS should cover most hosts of the next IPTA detections except near the Milky Way plane.","discovery_kind":"new_method","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Null K-correction is validated only in Ks; the SuperCOSMOS B-band conclusion at z≈0.36 needs K_B≈1.5–2 mag, which shifts the B reach down ~0.3–0.4 dex and likely erases the IPTA_20 margin at high mass.","rationale":"The paper is careful in propagating scatter, and the ETG and AGN calculations are clearly documented. I judge the reader's scaling-relation concern as real but already acknowledged and partly addressed; my stronger, more concrete objection is the unexamined B-band K-correction. The authors explicitly say they set the K-correction to zero in Section 3.1 and later assert this choice is negligible in Section 5, but the cited justification concerns only the Ks band. The B band is exactly where ETG SEDs have the 4000 Å break, and at the z≈0.36–0.5 redshifts reached by IPTA_20 and IPTA_30 the correction is not a small effect. Because the SuperCOSMOS completeness claim is the most falsifiable part of the abstract and hinges on B-band magnitudes, this omission is load-bearing. A template-SED recalculation settles it; if the curve crosses the PTA reach, the paper should condition acceptance on revising the completeness claim and moving the K-correction into the pipeline. I therefore retain the reader's CONDITIONAL recommendation, but on different grounds.","tokens_in":24952,"tokens_out":24877,"duration_ms":277990,"concrete_test":"Compute K_B(z) = 2.5 log10[(1+z) L_nu((1+z)nu_B) / L_nu(nu_B)] using an ETG template SED (e.g., Brown et al. 2014 or Polletta et al. 2007), insert it into the B-band distance-modulus relation instead of the zero-K version of Eq. 4, and regenerate the SuperCOSMOS curve in Figure 5. If the curve drops by ≳0.3 dex for M_tot≳10^9.5 M_sun and crosses the IPTA_20 black best-case reach curve, then the abstract's 'all binaries' statement fails for SuperCOSMOS and the conclusion should be downgraded to WISE.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central 'all detectable hosts are in WISE and SuperCOSMOS' claim rests on the B-band magnitude conversion. In Section 3.1 the authors set the K-correction to zero and justify it only in the Ks band, citing values in [-0.5,0] from Mannucci et al. 2001. The B-band step is then obtained from the empirical GLADE+ apparent-magnitude fit in Eq. 6, which is calibrated over a mostly low-redshift sample and carries no redshift dependence. For an ETG at z≈0.36, the observed B band corresponds to rest-frame ~330 nm, just shortward of the 4000 Å break, where the SED is fainter by ~1.5 mag; including the standard (1+z) bandwidth factor gives K_B≈1.5–2 mag. Since m_B enters the SuperCOSMOS reach as 5 log d = m_lim - M_B + 5 - K_B, a 1.5–2 mag K-correction reduces the maximum distance by 10^{K/5}≈2 (≈0.3–0.4 dex). Figure 5's SuperCOSMOS curve is close to the IPTA_20 best-case reach at M_tot≳10^9.5 M_sun, so this shift is exactly the size needed to make the survey incomplete for the farthest, most massive hosts. The Section 5 caveat that neglecting K-corrections does not significantly affect the results is supported only for Ks, not for B.","agreement_with_reader":"disagree"},"referee_report":{"model":"deepseek-v4-flash","summary":"This paper develops a pipeline for converting PTA-inferred supermassive black hole binary parameters (total mass and luminosity distance) into predicted apparent magnitudes of the host galaxy in the Ks, W1, and B bands, for two host scenarios: regular early-type galaxies and AGN. The authors simulate three future IPTA configurations (20, 25, and 30 year baselines), compute the maximum luminosity distance at which individual binaries can be detected as a function of mass, and compare those reaches with the nominal depths of 2MASS, WISE, and SuperCOSMOS. The central quantitative claim is that, for the IPTA_20 configuration, all detectable binary hosts outside the Galactic plane should be present in WISE and SuperCOSMOS, while 2MASS becomes incomplete at high masses and distances; longer-baseline arrays yield more incompleteness. The paper also demonstrates the pipeline on a mock detection from Petrov et al. (2024), converting GW posteriors into host magnitude distributions.","tokens_in":25253,"tokens_out":7584,"duration_ms":79733,"significance":"If the method is sound, it addresses a timely and practical problem: how to rank and select candidate host galaxies once PTAs resolve individual supermassive black hole binaries. The reach calculations are clearly described, the use of empirical scaling relations is transparent, and the Monte Carlo propagation of uncertainties is appropriate. The paper makes explicit, testable predictions about survey completeness that can be checked once a resolved source is found. However, the headline claim about SuperCOSMOS completeness rests on a K-correction assumption that is only justified in the Ks band and is not valid for the B band, and the posterior-conversion algorithm in Section 3.3 contains a statistical bias. These issues affect the central claims and need to be addressed before the results can be relied upon.","major_comments":[{"comment":"The null K-correction is justified only for the Ks band and is then implicitly applied to the B-band magnitudes. The text cites Mannucci et al. (2001) only for Ks, with values in [-0.5, 0], but at z ≈ 0.36 the observed B band samples rest-frame wavelengths near 330 nm, shortward of the 4000 Å break, where an early-type galaxy SED is much fainter and K_B ≈ 1.5-2 mag is expected. Since the distance modulus enters as 5 log d_L = m_lim - M_B + 5 - K_B, a K-correction of 1.5-2 mag reduces the SuperCOSMOS reach by 10^(K_B/5) ≈ 2, i.e., by about 0.3-0.4 dex in log d_L. Figure 5 shows the SuperCOSMOS curve lying close to the IPTA_20 best-case reach at M_tot ≳ 10^9.5 M_sun, so this shift is of exactly the size needed to erase the claimed margin. The statement in Section 5 that neglecting K-corrections does not significantly affect the results is therefore supported only for Ks, not for B. The central claim that all IPTA_20 detectable hosts are present in SuperCOSMOS should be recomputed with a redshift-dependent K_B, or the conclusion should be restricted to the WISE band.","section":"§3.1, Eq. (4) and Fig. 5"},{"comment":"The rejection-sampling procedure does not sample the stated target distribution. The proposal is obtained by drawing (M_tot, q, f_GW, h0) from the priors and then computing (M_chirp, d_L); this induces a non-uniform proposal density in the (M_chirp, d_L) plane. The acceptance probability is then taken as P(M_chirp, d_L)/P_max, with no division by the proposal density. Standard rejection sampling requires acceptance probability p(z)/(M q(z)), where q(z) is the proposal density. Omitting q(z) overweights regions where the prior predictive density of (M_chirp, d_L) is large. Consequently, the accepted (M_tot, d_L) samples, and therefore the magnitude distributions shown in Figure 7, are biased. A correct route is to use joint posterior samples of q from the GW analysis and transform each chirp-mass sample directly, or to include the proposal density in the acceptance ratio.","section":"§3.3, Steps 3-6"},{"comment":"The conversion from binary total mass to host brightness relies on using M_tot in the M_BH-M_bulge relation calibrated for single SMBHs, and on assuming that the resulting bulge mass equals the total stellar mass of an early-type galaxy. The authors acknowledge this caveat in Section 5, but the central survey-completeness claim is sensitive to the zero-point of this relation, so the conclusion would be more robust with a quantitative sensitivity test. Recomputing the reach curves with alternative scaling relations (e.g., Haring & Rix 2004, Kormendy & Ho 2013) or with a high-mass correction motivated by the recent GW background amplitude would show whether the 'all hosts detectable' conclusion survives plausible systematic offsets. As it stands, the prediction is tied to one empirical relation without a demonstrated robustness margin at the high-mass, high-redshift end where the SuperCOSMOS and IPTA_20 curves nearly intersect.","section":"§3.1, Eq. (2), and §5"}],"minor_comments":[{"comment":"The formula for the luminosity distance derived from the strain amplitude is typeset in a way that makes it difficult to parse; please check the published expression against the standard strain-distance relation and add parentheses around the prefactor for clarity.","section":"Eq. (13)"},{"comment":"In the sentence comparing the 95th percentile of m_B with the WISE x SuperCOSMOS catalog, the word 'above' should be clarified to mean fainter (larger magnitude), otherwise the direction of the 84% rejection statistic is ambiguous.","section":"§4.2, catalog comparison"},{"comment":"The inter-band apparent-magnitude calibrations are fit using the GLADE+ catalog, which is mostly at low redshift; the paper should state the redshift range of the galaxies used in the fit and explicitly discuss the extrapolation to z ~ 0.36, in addition to the K-correction issue.","section":"§3.1, Eqs. (5) and (6)"}],"recommendation":"major_revision","confidential_remarks":"The paper is within the scope of the journal and the proposed pipeline is potentially useful for the imminent era of resolved PTA sources. However, the B-band K-correction issue directly impacts the headline completeness claim, and the rejection-sampling bias affects the demonstrated posterior-conversion method. Both are fixable in revision, but I would not recommend acceptance before seeing revised reach curves that include a redshift-dependent K_B and a corrected posterior-conversion procedure."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Hi —\n\nPunchline: this paper builds a genuinely useful pipeline for turning a PTA source posterior into host-galaxy apparent magnitude distributions, and it does the uncertainty propagation carefully. But the abstract’s headline claim that WISE and SuperCOSMOS cover all IPTA_20 hosts is too optimistic, because the B-band K-correction is treated as null without support.\n\nWhat’s actually new: Arzoumanian et al. 2021 went from Ks magnitudes to SMBH masses; Truant et al. 2025 computed theoretical host brightnesses. Veronesi et al. go the other way—from a GW posterior to apparent magnitudes across Ks, W1, and B, including a rejection-sampling step that maps (chirp mass, strain, frequency) to (M_tot, d_L). The worked example using the Petrov et al. mock detection shows ~84% of galaxies in the localization region can be rejected on photometry alone. That is a practical result people will use.\n\nThe method itself is mostly sound. The ETG branch uses McConnell & Ma plus Cappellari; the AGN branch uses Eddington-ratio KDEs and bolometric corrections from real quasar samples. Section 5 openly acknowledges the M_BH–M_bulge scatter dominates the reach uncertainty and that the GWB amplitude may imply heavier SMBHs than the relation predicts. Those caveats are honest.\n\nThe soft spot is the null K-correction. Section 3.1 justifies it with Mannucci et al. values in Ks only. Then Eq. 6 maps Ks to B using a low-redshift GLADE+ fit with no redshift dependence. At z≈0.36 the observed B band is rest-frame ~330 nm, shortward of the 4000 Å break; K_B≈1.5–2 mag is standard. That shifts the SuperCOSMOS reach down by ~0.3–0.4 dex, and Figure 5 shows the margin at high M_tot is about that thin. So the Section 5 claim that neglecting K-corrections doesn’t affect results is not supported for B. The 2 Gpc reach is also the best-case (best sky, q=1, f=1e-8), a qualifier missing from the abstract.\n\nMinor: no code or data release, but the recipes are clear enough to reimplement.\n\nWho this is for: PTA multimessenger people planning host follow-up in the next decade. They should use the pipeline, but apply a proper K-correction before trusting the B-band completeness.\n\nIf this had come to me as a referee report, I would accept it for review—the method is worth having in the literature—but I would ask for the B-band K-correction to be fixed and the abstract’s completeness claim to be softened. The published version overstates that one point.","headline":"Useful PTA-host photometry pipeline, but the SuperCOSMOS completeness claim rests on an unjustified null K-correction in B.","tokens_in":25897,"tokens_out":4462,"would_cite":true,"duration_ms":43209,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"A PTA detection's posterior over binary mass and distance can be converted into a prediction of host-galaxy brightness; for the upcoming 20-year IPTA, those hosts should already be in the WISE and SuperCOSMOS surveys outside the Galactic…","keywords":["gravitational wave astronomy","supermassive black holes","pulsar timing arrays","host galaxy identification","galaxy scaling relations","electromagnetic counterparts","sky surveys"],"falsifier":"Find the securely identified host of a resolved PTA source and measure its stellar or bulge mass independently of the gravitational-wave inference; if the host's mass lies below the $M_{\\rm BH}$--$M_{\\rm bulge}$ relation's prediction at the inferred binary total mass, the conversion chain is biased and the claimed WISE/SuperCOSMOS completeness is too optimistic. A catalog check would also work: a host found to be fainter than the 5th percentile of the predicted magnitude distribution, in a band where the paper predicts detectability, would falsify the method's calibration for that system.","tokens_in":24680,"feed_emoji":"🔭","tokens_out":13341,"duration_ms":110599,"temperature":0.7,"pith_summary":"Pulsar timing arrays will soon resolve individual supermassive black hole binaries, but each detection will come with a localization region spanning hundreds to thousands of square degrees and a poorly constrained distance. This paper establishes a pipeline that converts the gravitational-wave parameters a PTA actually measures—chirp mass, strain amplitude, and frequency—into probability distributions for the apparent brightness of the host galaxy in the near-infrared $K_s$ band, the mid-infrared $W1$ band, and the optical $B$ band. The conversion is built for two host scenarios, a passive early-type galaxy and an active galactic nucleus, and it is then used to ask whether existing all-sky surveys can see the hosts of binaries that future International Pulsar Timing Array data releases could resolve. The paper's answer for a 20-year, 116-pulsar array is yes: outside the Galactic plane, all expected hosts should already be in the WISE and SuperCOSMOS catalogs, while 2MASS starts to miss the most massive hosts beyond 1 Gpc. That matters because brightness is a cheap, catalog-based filter for ranking and rejecting candidate host galaxies before any expensive follow-up.","feed_headline":"Hosts of PTA binaries should be in WISE and SuperCOSMOS catalogs","feed_subtitle":"A 20-year, 116-pulsar array reaches host galaxies out to 2 Gpc; only 2MASS misses the heaviest, most distant.","key_machinery":"The carrying mechanism is a chain of empirically calibrated scaling relations. For early-type hosts, the chain is: binary total mass $M_{\\rm tot}$ stands in for the single black hole mass in the $M_{\\rm BH}$--$M_{\\rm bulge}$ relation of McConnell & Ma (2013), giving a bulge mass that is assumed to equal the galaxy's total stellar mass; the stellar mass is converted to an absolute $K_s$-band magnitude through the Cappellari (2013) mass–luminosity relation; and the apparent $K_s$ magnitude (with distance and dust extinction) is converted into $W1$ and $B$ apparent magnitudes using linear inter-band relations calibrated on the GLADE+ catalog. For active hosts, the chain runs from $M_{\\rm tot}$ to Eddington luminosity, to bolometric luminosity through mass-binned Eddington-fraction distributions from Wu & Shen (2022), and then to band luminosities through bolometric-correction distributions built from Shang et al. (2011) and Runnoe et al. (2012). A separate rejection-sampling step converts the standard PTA posterior over chirp mass, strain amplitude, and frequency into a joint $M_{\\rm tot}$--$d_L$ distribution, which is what allows the method to start from real gravitational-wave search output rather than from assumed binary parameters. Uncertainties are propagated by random draws from every scatter and distribution in the chain, which is how the final magnitude predictions become probability distributions rather than point estimates.","core_discovery":"The central claim is that the mapping from a binary's total mass to its host's light is strong enough to be usable in reverse: start from the posterior distribution over binary total mass and luminosity distance delivered by a PTA search, apply empirical galaxy–black hole scaling relations sample by sample, and the result is a calibrated probability distribution for the host's apparent magnitude in several bands. The paper shows this for two host pictures: a regular early-type galaxy, where total mass is converted to bulge mass, then stellar mass, then $K_s$-band luminosity, then $W1$ and $B$ magnitudes; and an active galactic nucleus, where total mass sets the Eddington luminosity, an Eddington-ratio distribution sets the bolometric luminosity, and bolometric-correction distributions set the band luminosities. Applied to the reach of upcoming arrays, this yields the paper's headline comparisons: with a baseline of 20 years and 116 pulsars, similar to the next IPTA data release, binaries are detectable out to roughly 2 Gpc ($z\\sim0.36$), and the hosts of all such binaries should be present in WISE and SuperCOSMOS outside the Galactic plane, whereas 2MASS becomes incomplete for hosts of binaries above $10^{9.8}\\,M_\\odot$ beyond 1 Gpc. The same conversion, applied to one mock detection at signal-to-noise 8, produces magnitude distributions whose 5th-to-95th percentile spans about 10 to 17 magnitudes, and the $B$-band prediction alone would reject roughly 84% of catalog galaxies in the localization area as too dim to host the binary.","pith_inferences":["The paper does not construct a full ranking likelihood, but the same machinery could be run in reverse over a galaxy catalog: each catalog galaxy's photometry implies a prior over binary mass and distance, and multiplying that by the PTA posterior would rank candidates by joint gravitational-wave-plus-photometry probability rather than by magnitude percentiles alone.","The uncertainty budget implies a shift in where future effort pays off: the intrinsic scatter of the $M_{\\rm BH}$--$M_{\\rm bulge}$ relation dominates the uncertainty in survey reach, yet for a fixed detection it contributes only about 2% of the width of the magnitude distribution, so sharper host predictions will come mainly from tighter gravitational-wave parameter estimation rather than from imp","Because the best PTA sky positions lie near the Galactic plane, where WISE and SuperCOSMOS are masked, the completeness claim is conditional on sky position in a way that may matter for the first real detection; quantifying the overlap between the PTA sensitivity map and the catalogs' unmasked area is a natural next step.","The same conversion logic could be extended to X-ray and radio bands, which the paper discusses only as follow-up channels; doing so would let the initial photometric ranking be checked against future high-resolution imaging of candidate hosts."],"forward_implications":["A 20-year, 116-pulsar array similar to the next IPTA data release can detect binaries out to a luminosity distance of about 2 Gpc ($z\\sim0.36$) under optimistic assumptions, and the hosts of every such binary should be in WISE and SuperCOSMOS outside the Galactic plane.","2MASS becomes incomplete for hosts of binaries with total mass above about $10^{9.8}\\,M_\\odot$ at luminosity distances beyond 1 Gpc, so near-infrared-only selection will miss the heaviest, most distant systems.","With a 30-year, 200-pulsar array the reach extends past 3 Gpc ($z\\sim0.53$), and at those distances the three surveys become increasingly incomplete: in the $K_s$ and $B$ bands for early-type hosts and in the $K_s$ and $W1$ bands for active galactic nucleus hosts.","Applying the conversion to a mock signal-to-noise-8 detection, the $B$-band magnitude distribution alone would reject about 84% of the galaxies in the localization area as too faint, shrinking the candidate list before follow-up.","For a fixed binary mass, early-type galaxies and active galactic nuclei have similar $K_s$-band magnitudes, making the near-infrared the band least sensitive to the assumed host type."],"supporting_citations":[{"why":"Supplies the black hole mass–bulge mass scaling relation with intrinsic scatter that anchors the early-type-galaxy magnitude conversion; the paper inverts this relation using binary total mass.","marker":"N. J. McConnell & C.-P. Ma 2013"},{"why":"Provides the stellar-mass–to–$K_s$-band absolute magnitude relation used to turn bulge mass into galaxy brightness.","marker":"M. Cappellari 2013"},{"why":"Provides the GLADE+ observed galaxy photometry used to calibrate the linear $K_s$-to-$W1$ and $K_s$-to-$B$ inter-band magnitude relations.","marker":"G. Dálya et al. 2022"},{"why":"Supplies the quasar catalog whose mass-binned Eddington-fraction distributions set the AGN bolometric luminosity from binary total mass.","marker":"Q. Wu & Y. Shen 2022"},{"why":"Supplies the AGN spectral energy distributions from which band-specific bolometric corrections in $K_s$, $W1$, and $B$ are derived.","marker":"Z. Shang et al. 2011"},{"why":"Supplies the bolometric luminosities and redshifts for the same AGN sample, letting the bolometric corrections be computed across the redshift range of interest.","marker":"J. C. Runnoe et al. 2012"},{"why":"Provides the mock PTA detection posteriors, the IPTA_20 array configuration, and the detection framework that set the reach calculations and the worked example.","marker":"P. Petrov et al. 2024"},{"why":"Sets the 2MASS limiting magnitude $m_{K_s}=14.3$ used to judge near-infrared completeness for hosts.","marker":"M. F. Skrutskie et al. 2006"},{"why":"Sets the WISE limiting magnitude $m_{W1}=16.83$ used to judge mid-infrared completeness for hosts.","marker":"E. L. Wright et al. 2010"},{"why":"Sets the SuperCOSMOS limiting magnitude $m_B=20.79$ used to judge optical completeness for hosts.","marker":"J. A. Peacock et al. 2016"}],"fun_headline_variants":["PTA host galaxies mapped to EM observables","Binary host detection: WISE and SuperCOSMOS within reach","PTA sources: hosts visible in WISE and SuperCOSMOS","From GW to light: predicting PTA host galaxies","2 Gpc hosts: WISE and SuperCOSMOS see them all"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The load-bearing premise is that the $M_{\\rm BH}$--$M_{\\rm bulge}$ scaling relation measured for single black holes still holds when the total mass of a close binary is inserted in place of the single black hole mass, and that the resulting bulge mass is the full stellar mass of an early-type galaxy; if real hosts deviate from this relation, especially at the high masses the detected gravitational-wave background may be pointing to, the predicted magnitudes and the survey-completeness conclusions shift.","fun_headline_variants_meta":{"raw":{"variants":["PTA host galaxies mapped to EM observables","Binary host detection: WISE and SuperCOSMOS within reach","PTA sources: hosts visible in WISE and SuperCOSMOS","From GW to light: predicting PTA host galaxies","2 Gpc hosts: WISE and SuperCOSMOS see them all"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000519,"raw_usage":{"total_tokens":2648,"prompt_tokens":1216,"completion_tokens":1432,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":832,"completion_tokens_details":{"reasoning_tokens":1348}},"tokens_in":832,"tokens_out":1432,"duration_ms":9408,"temperature":1.0,"reasoning_tokens":1348,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-15T20:50:55.996232+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Find the securely identified host of a resolved PTA source and measure its stellar or bulge mass independently of the gravitational-wave inference; if the host's mass lies below the $M_{\\rm BH}$--$M_{\\rm bulge}$ relation's prediction at the inferred binary total mass, the conversion chain is biased and the claimed WISE/SuperCOSMOS completeness is too optimistic. A catalog check would also work: a host found to be fainter than the 5th percentile of the predicted magnitude distribution, in a band where the paper predicts detectability, would falsify the method's calibration for that system.","supporting_citations":[{"cited_title":"S., Wills, B","cited_arxiv_id":null,"evidence_quote":"Supplies the AGN spectral energy distributions from which band-specific bolometric corrections in $K_s$, $W1$, and $B$ are derived."},{"cited_title":"C., Brotherton, M","cited_arxiv_id":null,"evidence_quote":"Supplies the bolometric luminosities and redshifts for the same AGN sample, letting the bolometric corrections be computed across the redshift range of interest."},{"cited_title":"R., Charisi, M., & Ma, C.-P","cited_arxiv_id":null,"evidence_quote":"Provides the mock PTA detection posteriors, the IPTA_20 array configuration, and the detection framework that set the reach calculations and the worked example."},{"cited_title":"A., Hambly, N","cited_arxiv_id":null,"evidence_quote":"Sets the SuperCOSMOS limiting magnitude $m_B=20.79$ used to judge optical completeness for hosts."}],"review_version":1}