Rm Rms Research Articles

Revealing hidden structures in the Zone of Avoidance – a blind MeerKAT H i Survey of the Vela Supercluster

Abstract We conducted the MeerKAT Vela Supercluster survey, named Vela−$\rm {H}\, \scriptstyle \mathrm{I}$, to bridge the gap between the Vela SARAO MeerKAT Galactic Plane Survey (Vela−SMGPS, −2○ ≤ b ≤ 1○), and optical and near-infrared spectroscopic observations of the Vela Supercluster (hereafter Vela−OPT/NIR) at |b| ≳ 7○. Covering coordinates from 263○ ≤ ℓ ≤ 284○ and 1○ ≤ b ≤ 6.2○ above, and −6.7○ ≤ b ≤ −2○ below the Galactic Plane (GP), we sampled 667 fields spread across an area of ${\sim } \rm 242 ~deg^2$. With a beam size of ∼38″ × 31″, Vela−$\rm {H}\, \scriptstyle \mathrm{I}$ achieved a sensitivity of $\langle \rm rms \rangle = 0.74$ $\rm mJy\, beam^{-1}$ at 44.3 $\rm km\, s^{-1}$ velocity resolution over ∼67 hours of observations. We cataloged 719 galaxies, with only 211 (29%) previously documented in the literature, primarily through the HIZOA, 2MASX, and WISE databases. Among these known galaxies, only 66 had optical spectroscopic redshift information. We found marginal differences of less than one channel resolution for all galaxies in common between HIZOA and Vela−SMGPS, and a mean difference of 70 ± 15 $\rm km\, s^{-1}$ between optical and $\rm {H}\, \scriptstyle \mathrm{I}$ velocities. Combining data from Vela−SMGPS, Vela−$\rm {H}\, \scriptstyle \mathrm{I}$, and Vela−OPT/NIR confirmed the connection of the Hydra/Antlia filament across the GP and revealed a previously unknown diagonal wall at a heliocentric velocity range of 6500 − 8000 $\rm km\, s^{-1}$. Vela−$\rm {H}\, \scriptstyle \mathrm{I}$ reinforces the connection between the first wall at 18500 − 20000 $\rm km\, s^{-1}$ and the inner ZOA. The second wall seems to traverse the GP at 270○ ≤ ℓ ≤ 279○, where it appears that both walls intersect, jointly covering the velocity range 18500 − 21500 $\rm km\, s^{-1}$.

Long-term wide-band spectrotemporal studies of outbursting black hole candidate sources GX 339–4 and H 1743–322: AstroSat and NuSTAR results

ABSTRACT We present a comprehensive spectrotemporal analyses of recurrent outbursting black hole sources GX 339$-$4 and H 1743$-$322 using available AstroSat and NuSTAR archival observations during 2016–2024. The nature of the outburst profiles of both sources are examined using long-term MAXI/GSC and Swift/BAT light curves, and failed as well as successful outbursts are classified. Wide-band (0.5–60 keV) spectral modelling with disc (diskbb) and Comptonized (Nthcomp) components indicates that GX 339$-$4 transits from hard ($kT_{\rm bb}=0.12-0.77$ keV, $\Gamma _{\rm nth}=1.54-1.74$, and $L_{\rm bol}=0.91-11.56$ per cent $L_{\rm Edd}$) to soft state ($kT_{\rm in}~[\approx {kT}_{\rm bb}]=0.82-0.88$ keV, $\Gamma _{\rm nth}=1.46-3.26$, $L_{\rm {bol}}=19.59-30.06~{{\ \rm per\ cent}}L_{\rm Edd}$) via intermediate state ($kT_{\rm in}~[\approx {kT}_{\rm {bb}}]=0.56-0.88$ keV, $\Gamma _{\rm nth}=1.76-2.66$, $L_{\rm {bol}}=2.90-16.09~{{\ \rm per\ cent}}L_{\rm Edd}$), whereas H 1743$-$322 transits from quiescent to hard state ($\Gamma _{\rm nth}=1.57-1.71$, $L_{\rm {bol}}=2.08-3.48~{{\ \rm per\ cent}}L_{\rm Edd}$). We observe type-B and type-C quasi-periodic oscillations (QPOs) in GX 339$-$4 with increasing frequencies ($0.10 - 5.37$ Hz) along with harmonics. For H 1743$-$322, prominent type-C QPOs are observed in frequency range 0.22–1.01 Hz along with distinct harmonics. Energy-dependent power spectral studies reveal that fundamental QPO and harmonics disappear beyond 20 keV in GX 339$-$4, whereas fundamental QPO in H 1743$-$322 persists up to 40 keV. We also observe that type-C ${\rm QPO}_{\rm rms}\,\rm per\,cent$ decreases with energy for both sources although such variations appear marginal for type-B QPOs. Additionally, we report non-monotonic behaviour of photon index with plasma temperature and detection of annihilation line. Finally, we discuss the relevance of the observational findings in the context of accretion dynamics around black hole binaries.

XMM–Newton Ultra Narrow Deep Field survey – II. X-ray spectral analysis of the brightest AGN population

ABSTRACT In this work, we present the results of a detailed X-ray spectral analysis of the brightest active galactic nuclei (AGNs) detected in the XMM–Newton 1.75 Ms Ultra Narrow Deep Field. We analysed 23 AGNs that have a luminosity range of $\sim 10^{42} {\!-\!} 10^{46}\, \rm {erg}\, \rm {s}^{-1}$ in the $2 {\!-\!} 10\, \rm {keV}$ energy band, redshifts up to 2.66, and $\sim 10\,000$ X-ray photon counts in the $0.3{ \!-\! }10\, \rm {keV}$ energy band. Our analysis confirms the ‘Iwasawa–Taniguchi effect,’ an anticorrelation between the X-ray luminosity ($L_x$) and the Fe–k$\alpha$ equivalent width (${\rm EW}_{\rm Fe}$) possibly associated with the decreasing of the torus covering factor as the AGN luminosity increases. We investigated the relationship among black hole mass ($M_{\rm BH}$), $L_x$, and X-ray variability, quantified by the Normalized Excess Variance ($\sigma ^2_{\rm rms}$). Our analysis suggest an anticorrelation in both $M_{\rm BH} - \sigma ^2_{\rm rms}$ and $L_x- \sigma ^2_{\rm rms}$ relations. The first is described as $\sigma ^2_{\rm rms} \propto M^{-0.26 \pm 0.05}_{\rm BH}$, while the second presents a similar trend with $\sigma ^2_{\rm rms} \propto L_{x}^{-0.31 \pm 0.04}$. These results support the idea that the luminosity–variability anticorrelation is a byproduct of an intrinsic relationship between the BH mass and the X-ray variability, through the size of the emitting region. Finally, we found a strong correlation among the Eddington ratio ($\lambda _{\rm Edd}$), the hard X-ray photon index ($\Gamma$), and the illumination factor $\log (A)$, which is related to the ratio between the number of Compton scattered photons and the number of seed photons. The $\log (\lambda _{\rm Edd})-\Gamma -\log (A)$ plane could arise naturally from the connection between the accretion flow and the hot corona.

A new 2D fluid-MC hybrid approach for simulating nonequilibrium atmospheric pressure plasmas: density distribution of atomic oxygen in radio-frequency plasma jets in He/O2 mixtures

A spatially two dimensional fluid-MC hybrid (fluid-kinetic) simulation method is developed and applied to the COST reference microplasma jet operated in helium with an oxygen admixture of 0.5%, excited by a single frequency voltage waveform with f = 13.56 MHz and ϕrms=275 V. The simulation approach is based on a fluid model augmented by a Monte Carlo module that generates electron impact rates for the continuity equations solved by the fluid module. This method is capable of providing the same level of accuracy as PIC/MCC simulations with an agreement within 5%–10% at atmospheric pressure, while being significantly faster (with a speedup factor of 30 for serial to 50 for parallel implementation). The simulation results are compared to previous measurements of atomic oxygen densities (Steuer et al 2021 J. Phys. D: Appl. Phys. 54 355204), and show a very good agreement. It is found that the buildup and saturation of the atomic oxygen density distribution along the jet are due to the interplay of chemical and electron impact reactions as well as of the gas flow. Comparing the simulation results to that of Liu et al 2021 J. Phys. D: Appl. Phys. 54 275204, it is inferred that fluid models where a 2-term BE solver is used, fail to describe the COST jet in an accurate manner due to the underestimation of the electron impact rates.

Role of magnetic pressure forces in fluctuation dynamo saturation

ABSTRACT Using magnetohydrodynamic simulations of fluctuation dynamos in turbulent flows with rms Mach numbers $\mathcal {M}_{\rm rms}= 0.2, 1.1$, and 3, we show that magnetic pressure forces play a crucial role in dynamo saturation in supersonic flows. First, as expected when pressure forces oppose compression, an increase in anticorrelation between density and magnetic field strengths obtains even in subsonic flows with the anticorrelation arising from the intense but rarer magnetic structures. In supersonic flows, due to stronger compressive motions density and magnetic field strength continue to maintain a positive correlation. However, the degree of positive correlation decreases as the dynamo saturates. Secondly, we find that the unit vectors of ∇ρ and ∇B2 are preferentially antiparallel to each other in subsonic flows. This is indicative of magnetic pressure opposing compression. This antiparallel alignment persists in transonic and supersonic flows at dynamo saturation. However, compressive motions also lead to the emergence of a parallel alignment in these flows. Finally, we consider the work done against the components of the Lorentz force and the different sources of magnetic energy growth and dissipation. We show that while in subsonic flows, suppression of field line stretching is dominant in saturating the dynamo, the picture is different in supersonic flows. Both field line stretching and compression initially amplifies the field. However, growing magnetic pressure opposes further compression of magnetic flux which tends to reduce the compressive motions. Simultaneously, field line stretching also reduces. But, suppression of compressive amplification dominates the saturation of the dynamo.

On the Role of Roughness in the Indentation of Viscoelastic Solids

A numerical boundary element methodology is employed to understand how fractality intervenes when a 1D rigid rough profile indents a linear viscoelastic half-plane. The focus is, in particular, on the viscoelastic dissipation and how this is influenced by the profile statistical parameters, namely, the mean square roughness h_{rm rms} of the profile, the mean square slope m_{2} and the Hurst exponent H. Our numerical investigation, properly supported by a dimensional analysis, reveals that, in the one-dimensional case under investigation, the leading role is played by h_{rm rms} and, thus, mainly by the large scales of the rough spectrum. Clearly, on an experimental level, this implies that a simple measure of the roughness parameter h_{rm rms} is sufficient to determine the viscoelastic dissipation.

Cylinder-Flat Contact Mechanics with Surface Roughness

We study the nominal (ensemble averaged) contact pressure p(x) acting on a cylinder squeezed in contact with an elastic half space with random surface roughness. The contact pressure is Hertzian-like for alpha < 0.01 and Gaussian-like for alpha > 10, where the dimensionless parameter alpha = h_{rm rms}/delta is the ratio between the root-mean-square roughness amplitude and the penetration for the smooth surfaces case (Hertz contact).

SDSS-IV MaNGA: stellar population correlates with stellar root-mean-square velocity Vrms gradients or total-density-profile slopes at fixed effective velocity dispersion σe

ABSTRACT Galaxy properties are known to correlate most tightly with the galaxy effective stellar velocity dispersion σe. Here, we look for additional trends at fixed σe using 1339 galaxies (M* ≳ 6 × 109 M⊙) with different morphologies in the MaNGA (DR14) sample with integral-field spectroscopy data. We focus on the gradients (γrms ≡ σ(Re/4)/σe) of the stellar root-mean-square velocity ($V_{\rm rms} \equiv \sqrt{V^2 + \sigma ^2}$), which we show traces the total mass density gradient γtot derived from dynamical models and, more weakly, the bulge fraction. We confirm that γrms increases with σe, age, and metallicity. We additionally find that these correlations still exist at fixed σe, where galaxies with larger γrms are found to be older and more metal-rich. It means that mass density gradients contain information of the stellar population which is not fully accounted for by σe. This result puts an extra constraint on our understanding of galaxy quenching. We compare our results with galaxies in the IllustrisTNG hydrodynamical simulations and find that, at fixed σe, similar trends exist with age, the bulge fraction, and the total mass density slope but, unlike observations, no correlation with metallicity can be detected in the simulations.

Optical properties of a liquid-crystal microlens with an arrayed planar non-uniform spiral micro-coil electrode

A new type of liquid-crystal (LC) microlens with an arrayed planar non-uniform spiral micro-coil electrode is proposed. Arrayed cylindrical microbeam focusing and spherical microbeam focusing corresponding to a circular and an elliptical micro-coil are realized, respectively. By applying driving voltage signals over only one electrode plate of the proposed LC microlens, an orderly inclining of LC directors can be achieved in response to the generated electric field, and this is the first time such a method has been proposed to the best of our knowledge. Through adjusting driving voltage signals, the electrically tunable focusing properties are evaluated experimentally. Typical focusing performances such as an arrayed focal line with ${\sim} 1.75\,\,{\rm mm}$∼1.75mm focal length corresponding to a signal voltage of ${\sim}{45.6\,\,{\rm V}_{\rm rms}}$∼45.6Vrms and a focal point with ${\sim} 2.35\,\,{\rm mm}$∼2.35mm focal length corresponding to ${\sim}{55.0\,\,{\rm V}_{\rm rms}}$∼55.0Vrms are given, as well as several typical intermediate states. This research lays a solid basis for continuously developing LC microlens technology.

Decoupling of Current Balancing and Reference Tracking Control in Parallel Interleaved Converters

An attractive approach to increasing the output power and bandwidth of converters is through the parallel connection of multiple, subrated converter cells via mutually coupled inductors. Achieving a balanced contribution to the output current by all paralleled converter cells is critical; good reference tracking performance, however, should also be maintained. Since these two control tasks are coupled, tuning of the controller parameters is challenging. This article demonstrates a methodology for decoupling the output current reference tracking control task from the current balancing control. We show that once balancing and tracking controllers are decoupled, the controller parameter tuning can be conducted independently, simplifying design and analysis of controller performance. Experimental results are presented, which validate the proposed methodology, applied to a three-cell, parallel interleaved converter with cyclic cascade coupled inductor filter network, operating at 100 ${\rm V}_{\rm RMS}$ and 9 ${\rm A}_{\rm RMS}$ .

Kinetics and Clustering of Dust Particles in Supersonic Turbulence with Self-gravity

We present a simulation of isothermal supersonic (rms Mach number $\mathcal{M}_{\rm rms} \sim 3$) turbulent gas with inertial particles (dust) and self-gravity in statistical steady-state, which we compare with a corresponding simulation without self-gravity. The former is in steady state, but close to gravitationally unstable, since we match the scale of the simulation box with Jeans wavelength, which provides the strongest influence of gravity on the dynamics of gas and dust without causing irreversible gravitational collapses. We find that self-gravity does not cause any significant increase in clustering of particles, regardless of particle size, but heavy particles show elevated mean velocities in the presence of self-gravity. The speed distributions are significantly shifted to higher values compared to simulations without self-gravity, but maintains the same shape.

Constraining the properties of the magnetic turbulence in the Geminga region using HAWC γ-ray data

Observations of extended gamma-ray emission around Galactic cosmic-ray (CR) sources can be used as novel probes of interstellar magnetic fields. Using very-high-energy gamma-ray data from the HAWC Observatory, we place constraints on the properties of the magnetic turbulence within $\approx 25$ pc from Geminga. We inject and propagate individual CR electrons in 3D realizations of turbulent magnetic fields, calculate the resulting gamma-ray emission, and compare with HAWC measurements of this region. We find that HAWC data is compatible with expectations for Kolmogorov or Kraichnan turbulence, and can be well fitted for reasonable coherence lengths and strengths of the turbulence, despite implying a CR diffusion coefficient significantly smaller than those suggested by Galactic CR propagation codes. The best fit is found for a coherence length $L_{\rm c} \approx 1$ pc and a magnetic field strength $B_{\rm rms} \approx 3 \mu$G, and the preferred value for $L_{\rm c}$ increases with $B_{\rm rms}$. Moreover, the apparent lack of strong asymmetries in the observed emission allows us to constrain the coherence length to $L_{\rm c} \lesssim 5$ pc in this region.

A 0.36 μW/channel recorder for external ambulatory ECG recorders

There is an increasing demand for long-term ECG monitoring applications which are very low power, small size and capable of wireless data transmission. This paper presents an analog front-end and also modulator for long-term ECG recording purpose. The fully integrated system features three independent channels and a modulator. The analog front-end includes a voltage-to-time conversion and a tunable modulator to achieve a very low power consumption for wireless transmission of the data without analog to digital converter. The proposed system is designed and simulated in a $$0.18\,\upmu \hbox {m}$$ CMOS technology and occupies only $$0.245\,\mathrm{mm}^{2}$$ . It can record ECG signal with 9.2-bit resolution while consuming only $$0.36\,\upmu {\mathrm{W}}$$ per channel from a 0.9 V supply. Also, it can transmit data consuming just $$0.72\,{\upmu }\mathrm{W}$$ per channel from a 0.9 V supply. The input referred noise of the readout channel is $$2.01\,\upmu {\mathrm{V}}_{{{\rm rms}}}$$ .

Connecting the Cosmic Star Formation Rate with the Local Star Formation

Abstract We present a model that unifies the cosmic star formation rate (CSFR), obtained through the hierarchical structure formation scenario, with the (Galactic) local star formation rate (SFR). It is possible to use the SFR to generate a CSFR mapping through the density probability distribution functions commonly used to study the role of turbulence in the star-forming regions of the Galaxy. We obtain a consistent mapping from redshift z ∼ 20 up to the present (z = 0). Our results show that the turbulence exhibits a dual character, providing high values for the star formation efficiency ( 〈 ε 〉 ∼ 0.32 ) in the redshift interval z ∼ 3.5 – 20 and reducing its value to 〈 ε 〉 = 0.021 at z = 0. The value of the Mach number (  crit ), from which 〈 ε 〉 rapidly decreases, is dependent on both the polytropic index (Γ) and the minimum density contrast of the gas. We also derive Larson’s first law associated with the velocity dispersion ( 〈 V rms 〉 ) in the local star formation regions. Our model shows good agreement with Larson’s law in the ∼ 10 – 50 pc range, providing typical temperatures T 0 ∼ 10 – 80 K for the gas associated with star formation. As a consequence, dark matter halos of great mass could contain a number of halos of much smaller mass, and be able to form structures similar to globular clusters. Thus, Larson’s law emerges as a result of the very formation of large-scale structures, which in turn would allow the formation of galactic systems, including our Galaxy.

Baryons still trace dark matter: Probing CMB lensing maps for hidden isocurvature

Compensated isocurvature perturbations (CIPs) are primordial fluctuations that balance baryon and dark-matter isocurvature to leave the total matter density unperturbed. The effects of CIPs on the cosmic microwave background (CMB) anisotropies are similar to those produced by weak lensing of the CMB: smoothing of the power spectrum, and generation of non-Gaussian features. Previous work considered the CIP effects on the CMB power-spectrum but neglected to include the CIP effects on estimates of the lensing potential power spectrum (though its contribution to the non-Gaussian, connected, part of the CMB trispectrum). Here, the CIP contribution to the standard estimator for the lensing potential power-spectrum is derived, and along with the CIP contributions to the CMB power-spectrum, Planck data is used to place limits on the root-mean-square CIP fluctuations on CMB scales, $\Delta_{\rm rms}^2(R_{\rm CMB})$. The resulting constraint of $\Delta_{\rm rms}^2(R_{\rm CMB}) < 4.3 \times 10^{-3}$ using this new technique improves on past work by a factor of $\sim 3$. We find that for Planck data our constraints almost reach the sensitivity of the optimal CIP estimator. The method presented here is currently the most sensitive probe of the amplitude of a scale-invariant CIP power spectrum placing an upper limit of $A_{\rm CIP}< 0.017$ at 95% CL. Future measurements of the large-scale CMB lensing potential power spectrum could probe CIP amplitudes as low as $\Delta_{\rm rms}^2(R_{\rm CMB}) = 8 \times 10^{-5}$ ($A_{\rm CIP} = 3.2 \times 10^{-4}$).

Three-Level TAIPEI Rectifier—Analysis of Operation, Design Considerations, and Performance Evaluation

A new low-cost three-phase four-switch three-level zero-voltage-switching (ZVS) discontinuous-current-mode power-factor-correction boost rectifier, for short named the three-level TAIPEI rectifier, that achieves a low input-current total harmonic distortion (THD) and features ZVS of all the switches is introduced. Since in the proposed rectifier the voltage stress of the four switches is equal to one-half of the output voltage, the rectifier can utilize switches with a lower voltage rating that, generally, have lower conduction losses. To reduce the switching-frequency range and maximize the light-load efficiency, the control is implemented by a combination of variable-switching frequency and phase-shift pulse-width modulation control. Detailed design guidelines for and performance evaluation of a three-phase 6-kW prototype designed for the line-to-line voltage range from 340 $V_{{\rm RMS}}$ to 520 $V_{{\rm RMS}}$ are presented. The prototype rectifier exhibits efficiency in the 96%–98% range and achieves less than 5% input-current THD over the entire nominal input-voltage range (380–480 $V_{L-L,{\rm RMS}}$ ) and above 50% of full load.

A GMRT survey of regions towards the Taurus molecular cloud at 323 and 608 MHz

We present observations of three active sites of star formation in the Taurus Molecular Cloud complex taken at 323 and 608 MHz (90 and 50 cm, respectively) with the Giant Metrewave Radio Telescope (GMRT). Three pointings were observed as part of a pathfinder project, targeted at the young stellar objects (YSOs) L1551 IRS 5, T Tau and DG Tau (the results for these target sources were presented in a previous paper). In this paper, we search for other YSOs and present a survey comprising of all three fields; a by-product of the large instantaneous field of view of the GMRT. The resolution of the survey is of order 10 arcsec and the best rms noise at the centre of each pointing is of order $100\,\mu$Jy beam$^{-1}$ at 323 MHz and $50\,\mu$Jy beam$^{-1}$ at 608 MHz. We present a catalogue of 1815 and 687 field sources detected above $5\,\sigma_{\rm rms}$ at 323 and 608 MHz, respectively. A total of 440 sources were detected at both frequencies, corresponding to a total unique source count of 2062 sources. We compare the results with previous surveys and showcase a sample of extended extragalactic objects. Although no further YSOs were detected in addition to the target YSOs based on our source finding criteria, these data can be useful for targeted manual searches, studies of radio galaxies or to assist in the calibration of future observations with the Low Frequency Array (LOFAR) towards these regions.

Analysis of the Integrated SEPIC-Flyback Converter as a Single-Stage Single-Switch Power-Factor-Correction LED Driver

This paper proposes a new isolated single-stage single-switch power-factor-correction (S4 PFC) driver for supplying light-emitting diodes (LEDs) without electrolytic capacitor. In the proposed LED driver, the switch turns on under zero current switching (ZCS) condition. Also, it turns on at a voltage less than its nominal voltage stress, and therefore, the switch capacitive turn-on loss decreases too much extent. The leakage energy is absorbed, so there are no voltage spikes across the switch when the switch turns off. In this paper, operating principles of the proposed driver are discussed, and design considerations are presented. Also, a laboratory prototype for supplying a 21 W/30 V LED module from 220 ${\rm V}_{\rm rms}/50\,{\rm Hz}$ ac mains is implemented, and experimental results are presented to verify the theoretical analysis.

Large-Area Optical Switch Using Surface-Expandable Liquid Droplets

In this paper, we demonstrate a large-area optical switch using surface-expandable liquid droplets. These droplets are isolated by polymeric grids. The surrounding of the liquid droplets is filled with another immiscible liquid in order to suppress the gravitational effect. To obtain an optical switch, the droplets are doped with dye. In the voltage-off state, the droplets have minimal surface area-to-volume ratio. As a result, the aperture ratio (AR) is maximal. By applying a voltage, the generated dielectric force can expand the surface of the droplets, leading the AR to decrease. At $V = 60 {\rm V_{\rm rms}}$ , the AR reduces to zero. The optical switch is polarization insensitive. By further optimizing the device structure, this optical switch has promising applications in light shutters, switchable windows, and displays.

Search for compensated isocurvature perturbations with Planck power spectra

In the standard inflationary scenario, primordial perturbations are adiabatic. The amplitudes of most types of isocurvature perturbations are generally constrained by current data to be small. If, however, there is a baryon-density perturbation that is compensated by a dark-matter perturbation in such a way that the total matter density is unperturbed, then this compensated isocurvature perturbation (CIP) has no observable consequence in the cosmic microwave background (CMB) at linear order in the CIP amplitude. Here we search for the effects of CIPs on CMB power spectra to quadratic order in the CIP amplitude. An analysis of the Planck temperature data leads to an upper bound $\Delta_{\rm rms}^2 \leq 7.1\times 10^{-3}$, at the 68\% confidence level, to the variance $\Delta_{\rm rms}^2$ of the CIP amplitude. This is then strengthened to $\Delta_{\rm rms}^2\leq 5.0\times 10^{-3}$ if Planck small-angle polarization data are included. A cosmic-variance-limited CMB experiment could improve the $1\sigma$ sensitivity to CIPs to $\Delta^2_{\rm rms} \lesssim 9\times 10^{-4}$. It is also found that adding CIPs to the standard $\Lambda$CDM model can improve the fit of the observed smoothing of CMB acoustic peaks just as much as adding a non-standard lensing amplitude.