Luminosity Correlation Research Articles

Cosmic Star Formation History Measured at 1.4 GHz

Abstract We matched the 1.4 GHz local luminosity functions of star-forming galaxies (SFGs) and active galactic nuclei to the 1.4 GHz differential source counts from 0.25 μJy to 25 Jy using combinations of luminosity and density evolution. We present the most robust and complete local far-infrared (FIR)/radio luminosity correlation to date in a volume-limited sample of ≈4.3 × 103 nearby SFGs, finding that it is very tight but distinctly sublinear: L FIR ∝ L 1.4 GHz 0.85 . If the local FIR/radio correlation does not evolve, the evolving 1.4 GHz luminosity function of SFGs yields the evolving star formation rate density (SFRD) ψ(M ⊙ yr−1 Mpc−3) as a function of time since the Big Bang. The SFRD measured at 1.4 GHz grows rapidly at early times, peaks at “cosmic noon” when t ≈ 3 Gyr and z ≈ 2, and subsequently decays with an e-folding timescale τ = 3.2 Gyr. This evolution is similar to, but somewhat stronger than, SFRD evolution estimated from UV and FIR data.

The X-ray spectral and variability properties of typical radio-loud quasars

ABSTRACT We present X-ray spectral and long-term variability analyses of an unbiased sample of 361 optically selected radio-loud quasars (RLQs) utilizing sensitive serendipitous X-ray data from the Chandra and XMM-Newton archives. The spectral and temporal properties of RLQs are compared with those of radio-quiet quasars (RQQs) matched in L2500Å and z. The median power-law photon index (Γ) of RLQs is $1.84_{-0.01}^{+0.01}$, which is close to that of matched RQQs ($1.90_{-0.01}^{+0.02}$). No significant correlations between Γ and radio-loudness, Lx/Lx, rqq (the X-ray luminosity over that expected from the Lx–Luv relation for RQQs), redshift, or Eddington ratio are found for our RLQs. The stacked X-ray spectra of our RLQs show strong iron-line emission and a possible Compton-reflection hump. The intrinsic X-ray variability amplitude is ≈40 per cent for RLQs on time-scales of months-to-years in the rest frame, which is somewhat smaller than for the matched RQQs (≈60 per cent) on similar time-scales, perhaps due to the larger black hole masses and lower Eddington ratios in our RLQ sample. The X-ray spectral and variability results for our RLQs generally support the idea that the X-ray emission of typical RLQs is dominated by the disc/corona, as is also indicated by a recent luminosity correlation study.

Model-independently Calibrating the Luminosity Correlations of Gamma-Ray Bursts Using Deep Learning

Abstract Gamma-ray bursts (GRBs) detected at high redshift can be used to trace the Hubble diagram of the universe. However, the distance calibration of GRBs is not as easy as that of SNe Ia. For the calibration method based on the empirical luminosity correlations, there is an underlying assumption that the correlations should be universal over the whole redshift range. In this paper, we investigate the possible redshift dependence of six luminosity correlations with a completely model-independent deep-learning method. We construct a network combining the recurrent neural networks (RNN) and the Bayesian neural networks (BNN), where RNN is used to reconstruct the distance–redshift relation by training the network with the Pantheon compilation, and BNN is used to calculate the uncertainty of the reconstruction. Using the reconstructed distance–redshift relation of Pantheon, we test the redshift dependence of six luminosity correlations by dividing the full GRB sample into two subsamples (low-z and high-z subsamples), and find that only the E p − E γ relation has no evidence for redshift dependence. We use the E p − E γ relation to calibrate GRBs, and the calibrated GRBs give tight constraints on the flat ΛCDM model, with the best-fitting parameter Ω M = 0.307 − 0.073 + 0.065 .

A Large Population of Luminous Active Galactic Nuclei Lacking X-Ray Detections: Evidence for Heavy Obscuration?

Abstract We present a large sample of infrared-luminous candidate active galactic nuclei (AGNs) that lack X-ray detections in Chandra, XMM-Newton, and NuSTAR fields. We selected all optically detected SDSS sources with redshift measurements, combined additional broadband photometry from WISE, UKIDSS, 2MASS, and GALEX, and modeled the spectral energy distributions (SEDs) of our sample sources. We parameterize nuclear obscuration in our SEDs with and uncover thousands of powerful obscured AGNs that lack X-ray counterparts, many of which are identified as AGN candidates based on straightforward WISE photometric criteria. Using the observed luminosity correlation between rest-frame 2–10 keV ( ) and rest-frame AGN ( ), we estimate the intrinsic X-ray luminosities of our sample sources and combine these data with flux limits from X-ray catalogs to determine lower limits on nuclear obscuration. Using the ratio of intrinsic-to-observed X-ray luminosity ( ), we find a significant fraction of sources with column densities approaching cm–2, suggesting that multiwavelength observations are necessary to account for the population of heavily obscured AGNs. We simulate the underlying distribution for the X-ray non-detected sources in our sample through survival analysis, and confirm the presence of AGN activity via X-ray stacking. Our results point to a considerable population of extremely obscured AGNs undetected by current X-ray observatories.

Observations of the Disk/Jet Coupling of MAXI J1820+070 during Its Descent to Quiescence

Abstract Black hole X-ray binaries in the quiescent state (Eddington ratios typically ≲10−5) display softer X-ray spectra (photon indices Γ ∼ 2) compared to higher-luminosity black hole X-ray binaries in the hard state (Γ ∼ 1.7). However, the cause of this softening and its implications for the underlying accretion flow are still uncertain. Here, we present quasi-simultaneous X-ray and radio spectral monitoring of the black hole X-ray binary MAXI J1820+070 during the decay of its 2018 outburst and of a subsequent reflare in 2019, providing an opportunity to monitor a black hole X-ray binary as it actively transitions into quiescence. We probe 1–10 keV X-ray luminosities as low as L X ∼ 4 × 1032 erg s−1, equivalent to Eddington fractions of ∼4 × 10−7. During its decay toward quiescence, the X-ray spectrum of MAXI J1820+070 softens from Γ ∼ 1.7 to Γ ∼ 2, with the softening taking ∼30 days and completing at L X ≈ 1034 erg s−1 (≈10−5 L Edd). While the X-ray spectrum softens, the radio spectrum generally remains flat or inverted throughout the decay. We also find that MAXI J1820+070 follows a radio (L R)–X-ray luminosity correlation of the form L R ∝ L X 0.52±0.07, making it the fourth black hole system to follow the so-called “standard track” unbroken over several (in this case, four) decades in L X. Comparing the radio/X-ray spectral evolution(s) with the L R–L X plane, we find that the X-ray softening is consistent with X-rays produced by Comptonization processes in a radiatively inefficient accretion flow. We generally disfavor X-ray emission originating solely from within the jet, with the possible exception of X-rays produced via synchrotron self-Compton processes.

The Zwicky Transient Facility Bright Transient Survey. II. A Public Statistical Sample for Exploring Supernova Demographics*

Abstract We present a public catalog of transients from the Zwicky Transient Facility (ZTF) Bright Transient Survey, a magnitude-limited (m < 19 mag in either the g or r filter) survey for extragalactic transients in the ZTF public stream. We introduce cuts on survey coverage, sky visibility around peak light, and other properties unconnected to the nature of the transient, and show that the resulting statistical sample is spectroscopically 97% complete at <18 mag, 93% complete at <18.5 mag, and 75% complete at <19 mag. We summarize the fundamental properties of this population, identifying distinct duration–luminosity correlations in a variety of supernova (SN) classes and associating the majority of fast optical transients with well-established spectroscopic SN types (primarily SN Ibn and II/IIb). We measure the Type Ia SN and core-collapse (CC) SN rates and luminosity functions, which show good consistency with recent work. About 7% of CC SNe explode in very low-luminosity galaxies (M i > −16 mag), 10% in red-sequence galaxies, and 1% in massive ellipticals. We find no significant difference in the luminosity or color distributions between the host galaxies of SNe Type II and SNe Type Ib/c, suggesting that line-driven wind stripping does not play a major role in the loss of the hydrogen envelope from their progenitors. Future large-scale classification efforts with ZTF and other wide-area surveys will provide high-quality measurements of the rates, properties, and environments of all known types of optical transients and limits on the existence of theoretically predicted but as yet unobserved explosions.

Scampy – A sub-halo clustering and abundance matching based python interface for painting galaxies on the dark matter halo/sub-halo hierarchy

ABSTRACT We present a computational framework for ‘painting’ galaxies on top of the dark matter halo/sub-halo hierarchy obtained from N-body simulations. The method we use is based on the sub-halo clustering and abundance matching (SCAM) scheme which requires observations of the 1- and 2-point statistics of the target (observed) population we want to reproduce. This method is particularly tailored for high redshift studies and thereby relies on the observed high-redshift galaxy luminosity functions and correlation properties. The core functionalities are written in C++ and exploit Object Oriented Programming, with a wide use of polymorphism, to achieve flexibility and high computational efficiency. In order to have an easily accessible interface, all the libraries are wrapped in python and provided with an extensive documentation. We validate our results and provide a simple and quantitative application to reionization, with an investigation of physical quantities related to the galaxy population, ionization fraction, and bubble size distribution. The library is publicly available at https://github.com/TommasoRonconi/scampy with full documentation and examples at https://scampy.readthedocs.io.

Cosmology-independent Estimate of the Hubble Constant and Spatial Curvature using Time-delay Lenses and Quasars

Abstract With the distance sum rule in the Friedmann–Lemaître–Robertson–Walker metric, model-independent constraints on both the Hubble constant H 0 and spatial curvature can be obtained using strong lensing time-delay data and Type Ia supernovae (SNe Ia) luminosity distances. This method is limited by the relatively low redshifts of SNe Ia, however. Here, we propose using quasars as distance indicators, extending the coverage to encompass the redshift range of strong lensing systems. We provide a novel and improved method of determining H 0 and simultaneously. By applying this technique to the time-delay measurements of seven strong lensing systems and the known ultraviolet versus X-ray luminosity correlation of quasars, we constrain the possible values of both H 0 and , and find that km and . The measured is consistent with zero spatial curvature, indicating that there is no significant deviation from a flat universe. If we use flatness as a prior, we infer that km , representing a precision of 2.5%. If we further combine these data with the 1048 current Pantheon SNe Ia, our model-independent constraints can be further improved to km and . In every case, we find that the Hubble constant measured with this technique is strongly consistent with the value (∼74 km ) measured using the local distance ladder, as opposed to the value optimized by Planck.

Comprehensive analysis of the transient X-ray pulsar MAXI J1409−619

ABSTRACT We probe the properties of the transient X-ray pulsar MAXI J1409−619 through RXTE and Swift follow-up observations of the outburst in 2010. We are able to phase-connect the pulse arrival times for the 25 d episode during the outburst. We suggest that either an orbital model (with Porb ≃ 14.7(4) d) or a noise process due to random torque fluctuations (with Sr ≈ 1.3 × 10−18 Hz2 s−2 Hz−1) is plausible to describe the residuals of the timing solution. The frequency derivatives indicate a positive torque–luminosity correlation, which implies temporary accretion disc formation during the outburst. We also discover several quasi-periodic oscillations in company with their harmonics whose centroid frequencies decrease as the source flux decays. The variation of the pulsed fraction and spectral power-law index of the source with X-ray flux is interpreted as the sign of transition from a critical to a sub-critical accretion regime at the critical luminosity within the range of 6 × 1037–1.2 × 1038 erg s−1. Using pulse-phase-resolved spectroscopy, we show that the phases with higher flux tend to have lower photon indices, indicating that the polar regions produce spectrally harder emission.

The evolution of gamma-ray burst jet opening angle through cosmic time

ABSTRACT Jet opening angles of long gamma-ray bursts (lGRBs) appear to evolve in cosmic time, with lGRBs at higher redshifts being on average more narrowly beamed than those at lower redshifts. We examine the nature of this anticorrelation in the context of collimation by the progenitor stellar envelope. First, we show that the data indicate a strong correlation between gamma-ray luminosity and jet opening angle, and suggest this is a natural selection effect – only the most luminous GRBs are able to successfully launch jets with large opening angles. Then, by considering progenitor properties expected to evolve through cosmic time, we show that denser stars lead to more collimated jets; we argue that the apparent anticorrelation between opening angle and redshift can be accounted for if lGRB massive star progenitors at high redshifts have higher average density compared to those at lower redshifts. This may be viable for an evolving initial mass function (IMF) – under the assumption that average density scales directly with mass, this relationship is consistent with the form of the IMF mass evolution suggested in the literature. The jet angle–redshift anticorrelation may also be explained if the lGRB progenitor population is dominated by massive stars at high redshift, while lower redshift lGRBs allow for a greater diversity of progenitor systems (that may fail to collimate the jet as acutely). Overall, however, we find both the jet angle–redshift anticorrelation and jet angle–luminosity correlation are consistent with the conditions of jet launch through, and collimation by, the envelope of a massive star progenitor.

Dust-depleted Inner Disks in a Large Sample of Transition Disks through Long-baseline ALMA Observations

Abstract Transition disks with large inner dust cavities are thought to host massive companions. However, the disk structure inside the companion orbit and how material flows toward an actively accreting star remain unclear. We present a high-resolution continuum study of inner disks in the cavities of 38 transition disks. Measurements of the dust mass from archival Atacama Large Millimeter/Submillimeter Array observations are combined with stellar properties and spectral energy distributions to assemble a detailed picture of the inner disk. An inner dust disk is detected in 18 of 38 disks in our sample. Of the 14 resolved disks, 8 are significantly misaligned with the outer disk. The near-infrared excess is uncorrelated with the mm-dust mass of the inner disk. The size–luminosity correlation known for protoplanetary disks is recovered for the inner disks as well, consistent with radial drift. The inner disks are depleted in dust relative to the outer disk, and their dust mass is uncorrelated with the accretion rates. This is interpreted as the result of radial drift and trapping by planets in a low α (∼10−3) disk, or a failure of the α-disk model to describe angular momentum transport and accretion. The only disk in our sample with confirmed planets in the gap, PDS 70, has an inner disk with a significantly larger radius and lower inferred gas-to-dust ratio than other disks in the sample. We hypothesize that these inner disk properties and the detection of planets are due to the gap having only been opened recently by young, actively accreting planets.

A study of [O III]/[O II] lines ratio in type 1 active galactic nucleus: Influence of radio jets and Eddington ratio to narrow line region emission

AbstractWe analyze emission line properties and their correlations for 18,043 type 1 active galactic nucleus (AGN) in the range of 0.02 ≤ z ≤ 0.8, based on Sloan Digital Sky Survey Data Release 14 data. We complement the data with photometric measurements from ROSAT, GALEX, 2MASS, and FIRST. We find the following: (a) The average correlation between luminosity of [O III] and AGN luminosity is stronger than those for [O II] line. This is consistent with the stratified model of narrow line region (NLR). Furthermore, we also find a weak dependence of ionization degree with AGN luminosity. (b) The narrow lines luminosity and radio luminosity correlation is stronger for radio quiet AGN and weaker for radio loud (RL) AGN, most likely due to radio jets. A possible explanation is as the jets penetrate the NLR, the shock will ionize its gas, increase the narrow lines emission, and cause a bigger dispersion in the correlation for RL AGN. (c) The investigated narrow lines, [O II], [O III], Hβ, Hα, [N II], and [S II], show a significant trend of decreasing luminosity ratio relative to the broad Hβ luminosity where the slopes in the range of −0.26 to −0.50. We did not find any correlation of the trend slopes with ionization potential or critical density of the lines. We suggest that this correlation is due to decrease in covering factor of NLR as AGN luminosity increases. (d) The EV1 correlation is found in our data and represents change in Eddington ratio. By using L[O III]/L[O II] ratio, we found that the ionization degree decreases as Eddington ratio increases. We also confirm that objects with higher Eddington ratio tend to have narrower Hβ, stronger Fe II emission, and weaker [O III] strength. In contrast to that, objects with lower Eddington ratio tend to have broader Hβ, weaker Fe II emission, and higher [O III] strength.

Infrared properties of planetary nebulae with [WR] and wels central stars

ABSTRACT We report the infrared (IR) properties of planetary nebulae (PNe) with Wolf–Rayet (WR) type and wels central stars known to date and compare them with the IR properties of a sample of PNe with H-rich central stars. We use near-, mid-, and far-IR photometric data from archives to derive the IR properties of PNe. We have constructed IR colour–colour diagrams of PNe using measurements from 2MASS, IRAS, WISE, and Akari bands. [WR] PNe have a larger near-IR emission from the hot dust component and also show a tendency for stronger 12 μm emission as compared to the other two groups. Cool asymptotic giant branch dust properties of all PNe are found to be similar. We derived the dust colour temperatures, dust masses, dust-to-gas mass ratios, IR luminosities, and IR excess (IRE) of PNe for these three groups. [WR] PNe and wels-PNe tend to have larger mean values for dust mass when compared to the third group. The average dust-to-gas mass ratio is found to be similar for the three groups of PNe. While there is a strong correlation of dust temperature and IR luminosity with the age for the three groups of PNe, the dust mass, dust-to-gas mass ratios, and IRE are found to be non-varying as the PNe evolve. [WR] PNe and wels-PNe show very similar distribution of excitation classes and also show similar distribution with Galactic latitude.

Model-independent Distance Calibration and Curvature Measurement Using Quasars and Cosmic Chronometers

Abstract We present a new model-independent method to determine spatial curvature and to mitigate the circularity problem affecting the use of quasars as distance indicators. Cosmic-chronometer measurements are used to construct the curvature-dependent luminosity distance using a polynomial fit. Based on the reconstructed and the known ultraviolet versus X-ray luminosity correlation of quasars, we simultaneously place limits on the curvature parameter Ω K and the parameters characterizing the luminosity correlation function. This model-independent analysis suggests that a mildly closed universe ( ) is preferred at the 2.1σ level. With the calibrated luminosity correlation, we build a new data set consisting of 1598 quasar distance moduli, and use these calibrated measurements to test and compare the standard ΛCDM model and the R h = ct universe. Both models account for the data very well, though the optimized flat ΛCDM model has one more free parameter than R h = ct, and is penalized more heavily by the Bayes Information Criterion. We find that R h = ct is slightly favored over ΛCDM with a likelihood of ∼57.7% versus 42.3%.

An Amati-Like Correlation for Short Gamma-Ray Bursts

Gamma-ray bursts (GRBs) are by far the most powerful explosions in the universe. Over the past two decades, several GRB energy and luminosity correlations were discovered for long gamma-ray bursts, which are bursts whose observed duration exceeds 2 seconds. One important correlation, the Amati relation, involves the observed peak energy, Ep,obs, in the vFv spectrum and the equivalent isotropic energy, Eiso. For many years, it was believed that the Amati correlation applied only to long GRBs. In this paper, we use a recent data sample that includes both long and short GRBs to re-examine the issue of whether the Amati correlation applies to long GRBs only. Our results indicate that although short bursts do not follow the Amati relation in the strict sense, they do exhibit a correlation between the intrinsic peak energy, Ep,i, and Eiso that is very similar to the Amati relation but with a different normalization and slope. The paper also discusses the physical interpretation of this correlation in the context of the internal shock model.

Quasi-simultaneous radio and X-ray observations of Aql X-1 : probing low luminosities

ABSTRACT Aql X-1 is one of the best-studied neutron star low-mass X-ray binaries. It was previously targeted using quasi-simultaneous radio and X-ray observations during at least seven different accretion outbursts. Such observations allow us to probe the interplay between accretion inflow (X-ray) and jet outflow (radio). Thus far, these combined observations have only covered one order of magnitude in radio and X-ray luminosity range; this means that any potential radio–X-ray luminosity correlation, LR ∝ LXβ, is not well constrained (β ≈ 0.4–0.9, based on various studies) or understood. Here we present quasi-simultaneous Very Large Array and Swift-XRT observations of Aql X-1’s 2016 outburst, with which we probe one order of magnitude fainter in radio and X-ray luminosity compared to previous studies (6 × 1034 erg s−1 < LX <3 × 1035 erg s−1, i.e. the intermediate to low-luminosity regime between outburst peak and quiescence). The resulting radio non-detections indicate that Aql X-1’s radio emission decays more rapidly at low X-ray luminosities than previously assumed – at least during the 2016 outburst. Assuming similar behaviour between outbursts, and combining all available data in the hard X-ray state, this can be modelled as a steep β =$1.17^{+0.30}_{-0.21}$ power-law index or as a sharp radio cut-off at LX ≲ 5 × 1035 erg s−1 (given our deep radio upper limits at X-ray luminosities below this value). We discuss these results in the context of other similar studies.

Compact Disks in a High-resolution ALMA Survey of Dust Structures in the Taurus Molecular Cloud

Abstract We present a high-resolution (∼0.″12, ∼16 au, mean sensitivity of 50 μJy beam−1 at 225 GHz) snapshot survey of 32 protoplanetary disks around young stars with spectral type earlier than M3 in the Taurus star-forming region using the Atacama Large Millimeter Array. This sample includes most mid-infrared excess members that were not previously imaged at high spatial resolution, excluding close binaries and objects with high extinction, thereby providing a more representative look at disk properties at 1–2 Myr. Our 1.3 mm continuum maps reveal 12 disks with prominent dust gaps and rings, 2 of which are around primary stars in wide binaries, and 20 disks with no resolved features at the observed resolution (hereafter smooth disks), 8 of which are around the primary star in wide binaries. The smooth disks were classified based on their lack of resolved substructures, but their most prominent property is that they are all compact with small effective emission radii (R eff,95% ≲ 50 au). In contrast, all disks with R eff,95% of at least 55 au in our sample show detectable substructures. Nevertheless, their inner emission cores (inside the resolved gaps) have similar peak brightness, power-law profiles, and transition radii to the compact smooth disks, so the primary difference between these two categories is the lack of outer substructures in the latter. These compact disks may lose their outer disk through fast radial drift without dust trapping, or they might be born with small sizes. The compact dust disks, as well as the inner disk cores of extended ring disks, that look smooth at the current resolution will likely show small-scale or low-contrast substructures at higher resolution. The correlation between disk size and disk luminosity correlation demonstrates that some of the compact disks are optically thick at millimeter wavelengths.

New evidence for the ubiquity of prominent polar dust emission in AGN on tens of parsec scales

ABSTRACT The key ingredient of active galactic nuclei (AGN) unification, the dusty obscuring torus was so far held responsible for the observed mid-infrared (MIR) emission of AGN. However, the best studied objects with Very Large Telescope Interferometer (VLTI)/MID-infrared Interferometric instrument (MIDI) show that instead a polar dusty wind is dominating these wavelengths, leaving little room for a torus contribution. But is this wind a ubiquitous part of the AGN? To test this, we conducted a straightforward detection experiment, using the upgraded Very Large Telescope (VLT)/VLT Imager and Spectrometer for mid-InfraRed (VISIR) for deep subarcsecond resolution MIR imaging of a sample of nine [O iv]-bright, obscured AGN, all of which were predicted to have detectable polar emission. Indeed, the new data reveal such emission in all objects but one. We further estimate lower limits on the extent of the polar dust and show that the polar dust emission is dominating the total MIR emission of the AGN. These findings support the scenario that polar dust is not only ubiquitous in AGN but also an integral part of its structure, processing a significant part of the primary radiation. The polar dust has to be optically thin on average, which explains e.g. the small dispersion in the observed MIR–X-ray luminosity correlation. At the same time, it has to be taken into account when deriving covering factors of obscuring material from MIR to bolometric luminosity ratios. Finally, we find a new tentative trend of increasing MIR emission size with increasing Eddington ratio.

Luminosity–Luminosity Correlations in Flux-limited Multiwavelength Data

Abstract We explore the general question of correlations among different waveband luminosities in a flux-limited multiband observational data set. Such correlations, often observed for astronomical sources, may be either intrinsic or induced by the redshift evolution of the luminosities and the data truncation due to the flux limits. We first address this question analytically. We then use simulated flux-limited data with three different known intrinsic luminosity correlations and prescribed luminosity functions and evolution similar to the ones expected for quasars. We explore how the intrinsic nature of luminosity correlations can be deduced, including exploring the efficacy of partial correlation analysis with redshift binning in determining whether luminosity correlations are intrinsic and finding the form of the intrinsic correlation. By applying methods that we have developed in recent works, we show that we can recover the true cosmological evolution of the luminosity functions and the intrinsic correlations between the luminosities. Finally, we demonstrate the methods for determining intrinsic luminosity correlations on actual observed samples of quasars with mid-infrared, radio, and optical fluxes and redshifts, finding that the luminosity–luminosity correlation is significantly stronger between mid-infrared and optical than that between radio and optical luminosities, supporting the canonical jet-launching and heating model of active galaxies.

FSRQ/BL Lac dichotomy as the magnetized advective accretion process around black holes: a unified classification of blazars

The $Fermi$ blazar observations show a strong correlation between $\gamma$-ray luminosities and spectral indices. BL Lac objects are less luminous with harder spectra than flat-spectrum radio quasars (FSRQs). Interestingly FSRQs are evident to exhibit a Keplerian disc component along with a powerful jet. We compute the jet intrinsic luminosities by beaming corrections determined by different cooling mechanisms. Observed $\gamma$-ray luminosities and spectroscopic measurements of broad emission lines suggest a correlation of the accretion disc luminosity with jet intrinsic luminosity. Also, theoretical and observational inferences for these jetted sources indicate a signature of hot advective accretion flow and a dynamically dominant magnetic field at jet-footprint. Indeed it is difficult to imagine the powerful jet launching from a geometrically thin Keplerian disc. We propose a magnetized, advective disc-outflow symbiosis with explicit cooling to address a unified classification of blazars by controlling both the mass accretion rate and magnetic field strength. The large scale strong magnetic fields influence the accretion dynamics, remove angular momentum from the infalling matter, help in the formation of strong outflows/jets, and lead to synchrotron emissions simultaneously. We suggest that the BL Lacs are more optically thin and magnetically dominated than FSRQs at the jet-footprint to explain their intrinsic $\gamma$-ray luminosities.